├── .gitignore
├── test
    ├── export-test.mjs
    ├── index.html
    └── Lifecycle-test.mjs
├── CHANGELOG.md
├── src
    ├── natives
    │   ├── Event.mjs
    │   └── EventTarget.mjs
    ├── export.mjs
    ├── shims
    │   ├── Event.mjs
    │   ├── support.mjs
    │   └── EventTarget.mjs
    ├── StateChangeEvent.mjs
    └── Lifecycle.mjs
├── CONTRIBUTING.md
├── package.json
├── dist
    ├── lifecycle.native.mjs
    ├── lifecycle.mjs
    ├── lifecycle.es5.js
    ├── lifecycle.native.mjs.map
    ├── lifecycle.es5.js.map
    └── lifecycle.mjs.map
├── rollup.config.js
├── README.md
└── LICENSE


/.gitignore:
--------------------------------------------------------------------------------
1 | node_modules
2 | npm-debug.log
3 | .DS_Store
4 | 
5 | test/test-bundle.js
6 | test/test-bundle.js.map
7 | 
8 | demo
9 | 


--------------------------------------------------------------------------------
/test/export-test.mjs:
--------------------------------------------------------------------------------
1 | import lifecycle from '../src/export.mjs';
2 | import Lifecycle from '../src/Lifecycle.mjs';
3 | 
4 | describe('export', () => {
5 |   it(`is an instance of Lifecycle`, () => {
6 |     assert(lifecycle instanceof Lifecycle);
7 |   });
8 | });
9 | 


--------------------------------------------------------------------------------
/CHANGELOG.md:
--------------------------------------------------------------------------------
 1 | # Changelog
 2 | 
 3 | ### 0.1.2 (2019-08-27)
 4 | 
 5 | - Fix security issues in dependencies via npm audit
 6 | 
 7 | ### 0.1.1 (2018-08-03)
 8 | 
 9 | - Fix a bug due to Safari not dispatching the pagehide or visibilitychange events (#3)
10 | - Simplify the logic for `getCurrentState()` (#1)
11 | 
12 | ### 0.1.0 (2018-06-27)
13 | 
14 | - Initial public release
15 | 


--------------------------------------------------------------------------------
/src/natives/Event.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | export default Event;
17 | 


--------------------------------------------------------------------------------
/src/natives/EventTarget.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | export default EventTarget;
17 | 


--------------------------------------------------------------------------------
/src/export.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | import Lifecycle from './Lifecycle.mjs';
17 | 
18 | export default new Lifecycle();
19 | 


--------------------------------------------------------------------------------
/src/shims/Event.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | import {supportsConstructableEventTarget} from './support.mjs';
17 | 
18 | /**
19 |  * A minimal Event class shim.
20 |  * This is used if the browser doesn't natively support constructable
21 |  * EventTarget objects.
22 |  */
23 | class EventShim {
24 |   /**
25 |    * @param {string} type
26 |    */
27 |   constructor(type) {
28 |     this.type = type;
29 |   }
30 | }
31 | 
32 | export default supportsConstructableEventTarget ? Event : EventShim;
33 | 


--------------------------------------------------------------------------------
/src/StateChangeEvent.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | import Event from './shims/Event.mjs';
17 | 
18 | /**
19 |  * implements {IStateChangeEvent}
20 |  */
21 | export default class StateChangeEvent extends Event {
22 |   /**
23 |    * @param {string} type
24 |    * @param {!Object} initDict
25 |    */
26 |   constructor(type, initDict) {
27 |     super(type);
28 |     this.newState = initDict.newState;
29 |     this.oldState = initDict.oldState;
30 |     this.originalEvent = initDict.originalEvent;
31 |   }
32 | }
33 | 


--------------------------------------------------------------------------------
/src/shims/support.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | let supportsConstructableEventTarget;
17 | 
18 | try {
19 |   new EventTarget();
20 | 
21 |   // When transpiled with babel and rollup, the `IS_CODE_TRANSPILED` constant
22 |   // is replaced with the boolean `true`, so this statement will always
23 |   // evaluate to `false`. When not transpiled, it will be true.
24 |   supportsConstructableEventTarget = typeof IS_CODE_TRANSPILED === 'undefined';
25 | } catch (err) {
26 |   supportsConstructableEventTarget = false;
27 | }
28 | 
29 | export {supportsConstructableEventTarget};
30 | 


--------------------------------------------------------------------------------
/CONTRIBUTING.md:
--------------------------------------------------------------------------------
 1 | # How to Contribute
 2 | 
 3 | We'd love to accept your patches and contributions to this project. There are
 4 | just a few small guidelines you need to follow.
 5 | 
 6 | ## Contributor License Agreement
 7 | 
 8 | Contributions to this project must be accompanied by a Contributor License
 9 | Agreement. You (or your employer) retain the copyright to your contribution,
10 | this simply gives us permission to use and redistribute your contributions as
11 | part of the project. Head over to <https://cla.developers.google.com/> to see
12 | your current agreements on file or to sign a new one.
13 | 
14 | You generally only need to submit a CLA once, so if you've already submitted one
15 | (even if it was for a different project), you probably don't need to do it
16 | again.
17 | 
18 | ## Code reviews
19 | 
20 | All submissions, including submissions by project members, require review. We
21 | use GitHub pull requests for this purpose. Consult
22 | [GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
23 | information on using pull requests.
24 | 
25 | ## Community Guidelines
26 | 
27 | This project follows [Google's Open Source Community
28 | Guidelines](https://opensource.google.com/conduct/).
29 | 


--------------------------------------------------------------------------------
/package.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "name": "page-lifecycle",
 3 |   "version": "0.1.2",
 4 |   "description": "A JavaScript library to observe Page Lifecycle API states: https://github.com/WICG/page-lifecycle",
 5 |   "license": "Apache-2.0",
 6 |   "main": "dist/lifecycle.es5.js",
 7 |   "module": "dist/lifecycle.mjs",
 8 |   "scripts": {
 9 |     "test": "eslint *.js src/**/* test/*.mjs",
10 |     "build": "rollup -c"
11 |   },
12 |   "repository": {
13 |     "type": "git",
14 |     "url": "https://github.com/GoogleChromeLabs/page-lifecycle.git"
15 |   },
16 |   "bugs": {
17 |     "url": "https://github.com/GoogleChromeLabs/page-lifecycle/issues"
18 |   },
19 |   "homepage": "https://github.com/GoogleChromeLabs/page-lifecycle#readme",
20 |   "keywords": [
21 |     "page",
22 |     "lifecycle",
23 |     "unload",
24 |     "beforeunload",
25 |     "visibilityState",
26 |     "visibilitychange",
27 |     "active",
28 |     "passive",
29 |     "hidden",
30 |     "frozen",
31 |     "discarded",
32 |     "terminated"
33 |   ],
34 |   "author": {
35 |     "name": "Philip Walton",
36 |     "email": "philip@philipwalton.com",
37 |     "url": "http://philipwalton.com"
38 |   },
39 |   "devDependencies": {
40 |     "babel-core": "^6.26.3",
41 |     "babel-plugin-external-helpers": "^6.22.0",
42 |     "babel-preset-env": "^1.7.0",
43 |     "eslint": "^6.2.2",
44 |     "eslint-config-google": "^0.13.0",
45 |     "rollup": "^1.20.2",
46 |     "rollup-plugin-babel": "^4.3.3",
47 |     "rollup-plugin-multi-entry": "^2.1.0",
48 |     "rollup-plugin-replace": "^2.2.0",
49 |     "rollup-plugin-terser": "^5.1.1"
50 |   },
51 |   "eslintConfig": {
52 |     "root": true,
53 |     "env": {
54 |       "browser": true,
55 |       "es6": true,
56 |       "node": true,
57 |       "mocha": true
58 |     },
59 |     "globals": {
60 |       "assert": false,
61 |       "sinon": false,
62 |       "safari": false
63 |     },
64 |     "parserOptions": {
65 |       "ecmaVersion": 2018,
66 |       "sourceType": "module"
67 |     },
68 |     "extends": [
69 |       "eslint:recommended",
70 |       "google"
71 |     ]
72 |   }
73 | }
74 | 


--------------------------------------------------------------------------------
/dist/lifecycle.native.mjs:
--------------------------------------------------------------------------------
 1 | /*!
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | /*! lifecycle.native.mjs v0.1.1 */
16 | class e extends Event{constructor(e,t){super(e),this.newState=t.newState,this.oldState=t.oldState,this.originalEvent=t.originalEvent}}const t="active",s="passive",i="hidden",a="frozen",n="terminated",r="object"==typeof safari&&safari.pushNotification,h="onpageshow"in self,o=["focus","blur","visibilitychange","freeze","resume","pageshow",h?"pagehide":"unload"],c=e=>(e.preventDefault(),e.returnValue="Are you sure?"),d=e=>e.reduce((e,t,s)=>(e[t]=s,e),{}),u=[[t,s,i,n],[t,s,i,a],[i,s,t],[a,i],[a,t],[a,s]].map(d),l=(e,t)=>{for(let s,i=0;s=u[i];++i){const i=s[e],a=s[t];if(i>=0&&a>=0&&a>i)return Object.keys(s).slice(i,a+1)}return[]},f=()=>document.visibilityState===i?i:document.hasFocus()?t:s;class v extends EventTarget{constructor(){super();const e=f();this.e=e,this.t=[],this.s=this.s.bind(this),o.forEach(e=>addEventListener(e,this.s,!0)),r&&addEventListener("beforeunload",e=>{this.i=setTimeout(()=>{e.defaultPrevented||e.returnValue.length>0||this.a(e,i)},0)})}get state(){return this.e}get pageWasDiscarded(){return document.wasDiscarded||!1}addUnsavedChanges(e){!this.t.indexOf(e)>-1&&(0===this.t.length&&addEventListener("beforeunload",c),this.t.push(e))}removeUnsavedChanges(e){const t=this.t.indexOf(e);t>-1&&(this.t.splice(t,1),0===this.t.length&&removeEventListener("beforeunload",c))}a(t,s){if(s!==this.e){const i=this.e,a=l(i,s);for(let s=0;s<a.length-1;++s){const i=a[s],n=a[s+1];this.e=n,this.dispatchEvent(new e("statechange",{oldState:i,newState:n,originalEvent:t}))}}}s(e){switch(r&&clearTimeout(this.i),e.type){case"pageshow":case"resume":this.a(e,f());break;case"focus":this.a(e,t);break;case"blur":this.e===t&&this.a(e,f());break;case"pagehide":case"unload":this.a(e,e.persisted?a:n);break;case"visibilitychange":this.e!==a&&this.e!==n&&this.a(e,f());break;case"freeze":this.a(e,a)}}}var g=new v;export default g;
17 | //# sourceMappingURL=lifecycle.native.mjs.map
18 | 


--------------------------------------------------------------------------------
/test/index.html:
--------------------------------------------------------------------------------
 1 | <!DOCTYPE html>
 2 | <html>
 3 | <head>
 4 |   <meta charset="utf-8">
 5 |   <title>Mocha Tests</title>
 6 |   <!-- Mocha v5+ doesn't work with IE9-10 -->
 7 |   <link href="https://cdnjs.cloudflare.com/ajax/libs/mocha/4.1.0/mocha.min.css" rel="stylesheet">
 8 | </head>
 9 | <body>
10 |   <div id="mocha"></div>
11 |   <script src="https://cdnjs.cloudflare.com/ajax/libs/chai/4.1.2/chai.min.js"></script>
12 | 
13 |   <!-- Mocha v5+ doesn't work with IE9-10 -->
14 |   <script src="https://cdnjs.cloudflare.com/ajax/libs/mocha/4.1.0/mocha.min.js"></script>
15 | 
16 |   <!-- Sinon v6+ doesn't work with IE9-10 -->
17 |   <script src="https://cdnjs.cloudflare.com/ajax/libs/sinon.js/5.1.0/sinon.min.js"></script>
18 | 
19 |   <script>
20 |   mocha.ui('bdd');
21 | 
22 |   // Expose chai's assert globally.
23 |   self.assert = chai.assert;
24 |   </script>
25 | 
26 |   <!-- Loads the mjs or the es5 version of lifecycle.js library -->
27 |   <!-- depending on the browser's capabilities -->
28 |   <script type="module">
29 |     import lifecycle from '../src/export.mjs';
30 |     // Expose lifecycle globally so the tests will work in both
31 |     // the module and nomodule cases.
32 |     self.lifecycle = lifecycle;
33 |   </script>
34 |   <script defer nomodule src="../dist/lifecycle.es5.js"></script>
35 | 
36 |   <script type="module" src="../test/export-test.mjs"></script>
37 |   <script type="module" src="../test/Lifecycle-test.mjs"></script>
38 |   <script defer nomodule src="test-bundle.js"></script>
39 | 
40 |   <script defer>
41 |   var LOAD_EVENT = 'onpageshow' in self ? 'pageshow' : 'load';
42 | 
43 |   // Wait until the after the page is loaded so loading events don't
44 |   // interfere with the tests.
45 |   addEventListener(LOAD_EVENT, function fn() {
46 |     // Remove the event listener so it's only invoked once.
47 |     removeEventListener(LOAD_EVENT, fn);
48 | 
49 |     var runner = mocha.run();
50 |     var failedTests = [];
51 | 
52 |     runner.on('end', function() {
53 |       window.mochaResults = runner.stats;
54 |       window.mochaResults.reports = failedTests;
55 |     });
56 | 
57 |     runner.on('fail', function(test, err) {
58 |       var flattenTitles = function(test){
59 |         var titles = [];
60 |         while (test.parent.title){
61 |           titles.push(test.parent.title);
62 |           test = test.parent;
63 |         }
64 |         return titles.reverse();
65 |       };
66 | 
67 |       failedTests.push({
68 |         name: test.title,
69 |         result: false,
70 |         message: err.message,
71 |         stack: err.stack,
72 |         titles: flattenTitles(test)
73 |       });
74 |     });
75 |   });
76 |   </script>
77 | </body>
78 | </html>
79 | 


--------------------------------------------------------------------------------
/dist/lifecycle.mjs:
--------------------------------------------------------------------------------
 1 | /*!
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | /*! lifecycle.mjs v0.1.1 */
16 | let e;try{new EventTarget,e=!0}catch(t){e=!1}class t{constructor(){this.e={}}addEventListener(e,t,s=!1){this.t(e).push(t)}removeEventListener(e,t,s=!1){const i=this.t(e),a=i.indexOf(t);a>-1&&i.splice(a,1)}dispatchEvent(e){return e.target=this,Object.freeze(e),this.t(e.type).forEach(t=>t(e)),!0}t(e){return this.e[e]=this.e[e]||[]}}var s=e?EventTarget:t;class i{constructor(e){this.type=e}}var a=e?Event:i;class n extends a{constructor(e,t){super(e),this.newState=t.newState,this.oldState=t.oldState,this.originalEvent=t.originalEvent}}const r="active",h="passive",c="hidden",o="frozen",d="terminated",u="object"==typeof safari&&safari.pushNotification,v="onpageshow"in self,l=["focus","blur","visibilitychange","freeze","resume","pageshow",v?"pagehide":"unload"],g=e=>(e.preventDefault(),e.returnValue="Are you sure?"),f=e=>e.reduce((e,t,s)=>(e[t]=s,e),{}),b=[[r,h,c,d],[r,h,c,o],[c,h,r],[o,c],[o,r],[o,h]].map(f),p=(e,t)=>{for(let s,i=0;s=b[i];++i){const i=s[e],a=s[t];if(i>=0&&a>=0&&a>i)return Object.keys(s).slice(i,a+1)}return[]},E=()=>document.visibilityState===c?c:document.hasFocus()?r:h;class m extends s{constructor(){super();const e=E();this.s=e,this.i=[],this.a=this.a.bind(this),l.forEach(e=>addEventListener(e,this.a,!0)),u&&addEventListener("beforeunload",e=>{this.n=setTimeout(()=>{e.defaultPrevented||e.returnValue.length>0||this.r(e,c)},0)})}get state(){return this.s}get pageWasDiscarded(){return document.wasDiscarded||!1}addUnsavedChanges(e){!this.i.indexOf(e)>-1&&(0===this.i.length&&addEventListener("beforeunload",g),this.i.push(e))}removeUnsavedChanges(e){const t=this.i.indexOf(e);t>-1&&(this.i.splice(t,1),0===this.i.length&&removeEventListener("beforeunload",g))}r(e,t){if(t!==this.s){const s=this.s,i=p(s,t);for(let t=0;t<i.length-1;++t){const s=i[t],a=i[t+1];this.s=a,this.dispatchEvent(new n("statechange",{oldState:s,newState:a,originalEvent:e}))}}}a(e){switch(u&&clearTimeout(this.n),e.type){case"pageshow":case"resume":this.r(e,E());break;case"focus":this.r(e,r);break;case"blur":this.s===r&&this.r(e,E());break;case"pagehide":case"unload":this.r(e,e.persisted?o:d);break;case"visibilitychange":this.s!==o&&this.s!==d&&this.r(e,E());break;case"freeze":this.r(e,o)}}}var w=new m;export default w;
17 | //# sourceMappingURL=lifecycle.mjs.map
18 | 


--------------------------------------------------------------------------------
/src/shims/EventTarget.mjs:
--------------------------------------------------------------------------------
 1 | /*
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | 
16 | import {supportsConstructableEventTarget} from './support.mjs';
17 | 
18 | 
19 | /**
20 |  * A minimal EventTarget class shim.
21 |  * This is used if the browser doesn't natively support constructable
22 |  * EventTarget objects.
23 |  */
24 | class EventTargetShim {
25 |   /**
26 |    * Creates the event registry.
27 |    */
28 |   constructor() {
29 |     this._registry = {};
30 |   }
31 | 
32 |   /**
33 |    * @param {string} type
34 |    * @param {EventListener|function(!Event):(boolean|undefined)} listener
35 |    * @param {(boolean|!AddEventListenerOptions)=} opts
36 |    * @return {undefined}
37 |    * @see https://dom.spec.whatwg.org/#dom-eventtarget-addeventlistener
38 |    */
39 |   addEventListener(type, listener, opts = false) {
40 |     this._getRegistry(type).push(listener);
41 |   }
42 | 
43 |   /**
44 |    * @param {string} type
45 |    * @param {EventListener|function(!Event):(boolean|undefined)} listener
46 |    * @param {(boolean|!EventListenerOptions)=} opts
47 |    * @return {undefined}
48 |    * @see https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener
49 |    */
50 |   removeEventListener(type, listener, opts = false) {
51 |     const typeRegistry = this._getRegistry(type);
52 |     const handlerIndex = typeRegistry.indexOf(listener);
53 |     if (handlerIndex > -1) {
54 |       typeRegistry.splice(handlerIndex, 1);
55 |     }
56 |   }
57 | 
58 |   /**
59 |    * @param {!Event|!EventShim} evt
60 |    * @return {boolean}
61 |    * @see https://dom.spec.whatwg.org/#dom-eventtarget-dispatchevent
62 |    */
63 |   dispatchEvent(evt) {
64 |     // Set the target then freeze the event object to prevent modification.
65 |     evt.target = this;
66 |     Object.freeze(evt);
67 | 
68 |     this._getRegistry(evt.type).forEach((listener) => listener(evt));
69 |     return true;
70 |   }
71 | 
72 |   /**
73 |    * Returns an array of handlers associated with the passed event type.
74 |    * If no handlers have been registered, an empty array is returned.
75 |    * @private
76 |    * @param {string} type The event type.
77 |    * @return {!Array} An array of handler functions.
78 |    */
79 |   _getRegistry(type) {
80 |     return this._registry[type] = (this._registry[type] || []);
81 |   }
82 | }
83 | 
84 | export default supportsConstructableEventTarget ? EventTarget : EventTargetShim;
85 | 


--------------------------------------------------------------------------------
/rollup.config.js:
--------------------------------------------------------------------------------
  1 | /*
  2 |  Copyright 2018 Google Inc. All Rights Reserved.
  3 |  Licensed under the Apache License, Version 2.0 (the "License");
  4 |  you may not use this file except in compliance with the License.
  5 |  You may obtain a copy of the License at
  6 | 
  7 |      http://www.apache.org/licenses/LICENSE-2.0
  8 | 
  9 |  Unless required by applicable law or agreed to in writing, software
 10 |  distributed under the License is distributed on an "AS IS" BASIS,
 11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 12 |  See the License for the specific language governing permissions and
 13 |  limitations under the License.
 14 | */
 15 | 
 16 | const path = require('path');
 17 | const babel = require('rollup-plugin-babel');
 18 | const multiEntry = require('rollup-plugin-multi-entry');
 19 | const replace = require('rollup-plugin-replace');
 20 | const {terser} = require('rollup-plugin-terser');
 21 | 
 22 | 
 23 | const pkg = require('./package.json');
 24 | 
 25 | const BANNER = `/*!
 26 |  Copyright 2018 Google Inc. All Rights Reserved.
 27 |  Licensed under the Apache License, Version 2.0 (the "License");
 28 |  you may not use this file except in compliance with the License.
 29 |  You may obtain a copy of the License at
 30 | 
 31 |      http://www.apache.org/licenses/LICENSE-2.0
 32 | 
 33 |  Unless required by applicable law or agreed to in writing, software
 34 |  distributed under the License is distributed on an "AS IS" BASIS,
 35 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 36 |  See the License for the specific language governing permissions and
 37 |  limitations under the License.
 38 | */`;
 39 | 
 40 | const generateBundleOpts = (file, {transpile, useNatives} = {}) => {
 41 |   const plugins = [];
 42 | 
 43 |   if (useNatives) {
 44 |     plugins.push({
 45 |       resolveId: (importee, importer) => {
 46 |         if (importee.includes('/shims/')) {
 47 |           return path.resolve(
 48 |               path.dirname(importer),
 49 |               importee.replace('/shims/', '/natives/'));
 50 |         }
 51 |       },
 52 |     });
 53 |   }
 54 | 
 55 |   if (transpile) {
 56 |     plugins.push(replace({
 57 |       'IS_CODE_TRANSPILED': JSON.stringify(true),
 58 |     }));
 59 |     plugins.push(babel({
 60 |       presets: [['env', {modules: false}]],
 61 |       plugins: ['external-helpers'],
 62 |     }));
 63 |   } else {
 64 |     plugins.push(replace({
 65 |       'IS_CODE_TRANSPILED': JSON.stringify(undefined),
 66 |     }));
 67 |   }
 68 | 
 69 |   const terserOpts = {
 70 |     output: {
 71 |       comments: /^!/,
 72 |     },
 73 |     compress: true,
 74 |     mangle: {
 75 |       toplevel: true,
 76 |     },
 77 |   };
 78 |   if (!transpile) {
 79 |     // Mangling properties doesn't work with the class transformations done
 80 |     // by Babel, since Babel defines class methods using their string names
 81 |     // .(passed to `Object.defineProperty()`) and strings are not minifed
 82 |     // by terser.
 83 |     terserOpts.mangle.properties = {
 84 |       regex: /^_/,
 85 |     };
 86 |   }
 87 |   plugins.push(terser(terserOpts));
 88 | 
 89 |   return {
 90 |     input: 'src/export.mjs',
 91 |     output: {
 92 |       file,
 93 |       format: transpile ? 'umd' : 'es',
 94 |       dir: 'dist',
 95 |       name: 'lifecycle',
 96 |       banner: `${BANNER}\n\n/*! ${file} v${pkg.version} */\n`,
 97 |       sourcemap: true,
 98 |     },
 99 |     plugins,
100 |   };
101 | };
102 | 
103 | module.exports = [
104 |   generateBundleOpts('lifecycle.mjs'),
105 |   generateBundleOpts('lifecycle.native.mjs', {useNatives: true}),
106 |   generateBundleOpts('lifecycle.es5.js', {transpile: true}),
107 | 
108 |   {
109 |     input: 'test/*-test.mjs',
110 |     output: {
111 |       file: 'test-bundle.js',
112 |       format: 'iife',
113 |       dir: 'test',
114 |     },
115 |     plugins: [
116 |       multiEntry(),
117 |       babel({
118 |         presets: [['env', {modules: false}]],
119 |         plugins: ['external-helpers'],
120 |       }),
121 |     ],
122 |     watch: {
123 |       include: ['src/**/*.mjs', 'test/**/*.mjs'],
124 |     },
125 |   },
126 | ];
127 | 


--------------------------------------------------------------------------------
/dist/lifecycle.es5.js:
--------------------------------------------------------------------------------
 1 | /*!
 2 |  Copyright 2018 Google Inc. All Rights Reserved.
 3 |  Licensed under the Apache License, Version 2.0 (the "License");
 4 |  you may not use this file except in compliance with the License.
 5 |  You may obtain a copy of the License at
 6 | 
 7 |      http://www.apache.org/licenses/LICENSE-2.0
 8 | 
 9 |  Unless required by applicable law or agreed to in writing, software
10 |  distributed under the License is distributed on an "AS IS" BASIS,
11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 |  See the License for the specific language governing permissions and
13 |  limitations under the License.
14 | */
15 | /*! lifecycle.es5.js v0.1.1 */
16 | !function(e,t){"object"==typeof exports&&"undefined"!=typeof module?module.exports=t():"function"==typeof define&&define.amd?define(t):e.lifecycle=t()}(this,function(){"use strict";var e=void 0;try{new EventTarget,e=!1}catch(t){e=!1}var t="function"==typeof Symbol&&"symbol"==typeof Symbol.iterator?function(e){return typeof e}:function(e){return e&&"function"==typeof Symbol&&e.constructor===Symbol&&e!==Symbol.prototype?"symbol":typeof e},n=function(e,t){if(!(e instanceof t))throw new TypeError("Cannot call a class as a function")},i=function(){function e(e,t){for(var n=0;n<t.length;n++){var i=t[n];i.enumerable=i.enumerable||!1,i.configurable=!0,"value"in i&&(i.writable=!0),Object.defineProperty(e,i.key,i)}}return function(t,n,i){return n&&e(t.prototype,n),i&&e(t,i),t}}(),r=function(e,t){if("function"!=typeof t&&null!==t)throw new TypeError("Super expression must either be null or a function, not "+typeof t);e.prototype=Object.create(t&&t.prototype,{constructor:{value:e,enumerable:!1,writable:!0,configurable:!0}}),t&&(Object.setPrototypeOf?Object.setPrototypeOf(e,t):e.__proto__=t)},a=function(e,t){if(!e)throw new ReferenceError("this hasn't been initialised - super() hasn't been called");return!t||"object"!=typeof t&&"function"!=typeof t?e:t},s=function(){function e(){n(this,e),this._registry={}}return i(e,[{key:"addEventListener",value:function(e,t){this._getRegistry(e).push(t)}},{key:"removeEventListener",value:function(e,t){var n=this._getRegistry(e),i=n.indexOf(t);i>-1&&n.splice(i,1)}},{key:"dispatchEvent",value:function(e){return e.target=this,Object.freeze(e),this._getRegistry(e.type).forEach(function(t){return t(e)}),!0}},{key:"_getRegistry",value:function(e){return this._registry[e]=this._registry[e]||[]}}]),e}(),o=e?EventTarget:s,u=e?Event:function e(t){n(this,e),this.type=t},f=function(e){function t(e,i){n(this,t);var r=a(this,(t.__proto__||Object.getPrototypeOf(t)).call(this,e));return r.newState=i.newState,r.oldState=i.oldState,r.originalEvent=i.originalEvent,r}return r(t,u),t}(),c="active",h="passive",d="hidden",l="frozen",p="terminated",v="object"===("undefined"==typeof safari?"undefined":t(safari))&&safari.pushNotification,y=["focus","blur","visibilitychange","freeze","resume","pageshow","onpageshow"in self?"pagehide":"unload"],g=function(e){return e.preventDefault(),e.returnValue="Are you sure?"},_=[[c,h,d,p],[c,h,d,l],[d,h,c],[l,d],[l,c],[l,h]].map(function(e){return e.reduce(function(e,t,n){return e[t]=n,e},{})}),b=function(){return document.visibilityState===d?d:document.hasFocus()?c:h};return new(function(e){function t(){n(this,t);var e=a(this,(t.__proto__||Object.getPrototypeOf(t)).call(this)),i=b();return e._state=i,e._unsavedChanges=[],e._handleEvents=e._handleEvents.bind(e),y.forEach(function(t){return addEventListener(t,e._handleEvents,!0)}),v&&addEventListener("beforeunload",function(t){e._safariBeforeUnloadTimeout=setTimeout(function(){t.defaultPrevented||t.returnValue.length>0||e._dispatchChangesIfNeeded(t,d)},0)}),e}return r(t,o),i(t,[{key:"addUnsavedChanges",value:function(e){!this._unsavedChanges.indexOf(e)>-1&&(0===this._unsavedChanges.length&&addEventListener("beforeunload",g),this._unsavedChanges.push(e))}},{key:"removeUnsavedChanges",value:function(e){var t=this._unsavedChanges.indexOf(e);t>-1&&(this._unsavedChanges.splice(t,1),0===this._unsavedChanges.length&&removeEventListener("beforeunload",g))}},{key:"_dispatchChangesIfNeeded",value:function(e,t){if(t!==this._state)for(var n=function(e,t){for(var n,i=0;n=_[i];++i){var r=n[e],a=n[t];if(r>=0&&a>=0&&a>r)return Object.keys(n).slice(r,a+1)}return[]}(this._state,t),i=0;i<n.length-1;++i){var r=n[i],a=n[i+1];this._state=a,this.dispatchEvent(new f("statechange",{oldState:r,newState:a,originalEvent:e}))}}},{key:"_handleEvents",value:function(e){switch(v&&clearTimeout(this._safariBeforeUnloadTimeout),e.type){case"pageshow":case"resume":this._dispatchChangesIfNeeded(e,b());break;case"focus":this._dispatchChangesIfNeeded(e,c);break;case"blur":this._state===c&&this._dispatchChangesIfNeeded(e,b());break;case"pagehide":case"unload":this._dispatchChangesIfNeeded(e,e.persisted?l:p);break;case"visibilitychange":this._state!==l&&this._state!==p&&this._dispatchChangesIfNeeded(e,b());break;case"freeze":this._dispatchChangesIfNeeded(e,l)}}},{key:"state",get:function(){return this._state}},{key:"pageWasDiscarded",get:function(){return document.wasDiscarded||!1}}]),t}())});
17 | //# sourceMappingURL=lifecycle.es5.js.map
18 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
  1 | # PageLifecycle.js
  2 | 
  3 | - [Overview](#overview)
  4 | - [Installation](#installation)
  5 | - [Usage](#usage)
  6 | - [API](#api)
  7 |   - [Properties](#properties)
  8 |   - [Methods](#methods)
  9 |   - [Events](#events)
 10 | - [Browser Support](#browser-support)
 11 | 
 12 | 
 13 | ## Overview
 14 | 
 15 | PageLifecycle.js is a tiny JavaScript library (<1K gzipped) that allows developers to easily observe [Page Lifecycle API](https://developers.google.com/web/updates/2018/07/page-lifecycle-api) state changes and implement [Page Lifecycle best practices](https://developers.google.com/web/updates/2018/07/page-lifecycle-api#developer-recommendations-for-each-state) consistently across all browsers.
 16 | 
 17 | **▶️ View demo: [page-lifecycle.glitch.me](https://page-lifecycle.glitch.me/) 👀**
 18 | 
 19 | ## Installation
 20 | 
 21 | You can install this library from npm by running:
 22 | 
 23 | ```sh
 24 | npm install --save-dev page-lifecycle
 25 | ```
 26 | 
 27 | ## Usage
 28 | 
 29 | Releases of this library include three minified, production-ready versions:
 30 | 
 31 | **1. ES5: [`dist/lifecycle.es5.js`](/dist/lifecycle.es5.js)** (UMD) ⭐
 32 | 
 33 | Use this version for maximum compatibility with legacy browsers (that can't run ES2015+ code).
 34 | 
 35 | As a UMD bundle, it can be required in CommonJS or AMD environments, or it can be loaded with a script tag as the browser global `lifecycle`.
 36 | 
 37 | ```html
 38 | <script defer src="/path/to/lifecycle.es5.js"></script>
 39 | <script defer>
 40 | lifecycle.addEventListener('statechange', function(event) {
 41 |   console.log(event.oldState, event.newState);
 42 | });
 43 | </script>
 44 | ```
 45 | 
 46 | **2. ES2015: [`dist/lifecycle.mjs`](/dist/lifecycle.mjs)** (ESM) 🔥
 47 | 
 48 | Use this version if you only support ES module-capable browsers or if you're using `<script type="module">` and the `nomodule` fallback [to conditionally target modern browsers](https://philipwalton.com/articles/deploying-es2015-code-in-production-today/).
 49 | 
 50 | ```html
 51 | <script type="module">
 52 | import lifecycle from '/path/to/page-lifecycle.mjs';
 53 | 
 54 | lifecycle.addEventListener('statechange', function(event) {
 55 |   console.log(event.oldState, event.newState);
 56 | });
 57 | </script>
 58 | ```
 59 | 
 60 | 
 61 | **3. ES2015 (native): [`dist/lifecycle.native.mjs`](/dist/lifecycle.native.mjs)** (ESM w/o `EventTarget` and `Event` shims) ⚠️
 62 | 
 63 | Use this version if you're only targeting browsers that [support extending `EventTarget` and `Event` constructors](https://www.chromestatus.com/features/5721972856061952).
 64 | 
 65 | *Note: this version is the smallest but will only work in some browsers. The implementation instructions are the same as the ES2015 version above.*
 66 | 
 67 | ## API
 68 | 
 69 | The PageLifecycle.js library exports a `lifecycle` object, which is a singleton instance of the [`Lifecycle`](/src/Lifecycle.mjs) class. The `Lifecycle` class has the following properties, methods, and events:
 70 | 
 71 | ### Properties
 72 | 
 73 | <table>
 74 |   <tr valign="top">
 75 |     <th align="left">Name</th>
 76 |     <th align="left">Type</th>
 77 |     <th align="left">Description</th>
 78 |   </tr>
 79 |   <tr valign="top">
 80 |     <td><code>state</code></td>
 81 |     <td><code>string</code></td>
 82 |     <td>
 83 |       Returns the current Page Lifecycle state.
 84 |     </td>
 85 |   </tr>
 86 |   <tr valign="top">
 87 |     <td><code>pageWasDiscarded</code></td>
 88 |     <td><code>boolean</code></td>
 89 |     <td>
 90 |       Returns the value of <code>document.wasDiscarded</code> (or <code>false</code> if not present).
 91 |     </td>
 92 |   </tr>
 93 | </table>
 94 | 
 95 | ### Methods
 96 | 
 97 | <table>
 98 |   <tr valign="top">
 99 |     <th align="left">Name</th>
100 |     <th align="left">Description</th>
101 |   </tr>
102 |   <tr valign="top">
103 |     <td><code>addEventListener</code></td>
104 |     <td>
105 |       <p><strong>Parameters:</strong></p>
106 |       <ul>
107 |         <li><em>type</em>: <code>string</code></li>
108 |         <li><em>listener</em>: <code>function(Event)</code></li>
109 |       </ul>
110 |       <p>Adds a callback function to be invoked whenever the passed event type is detected. <em>(Note: at the moment only the "statechange" event type is supported.)</em></p>
111 |     </td>
112 |   </tr>
113 |   <tr valign="top">
114 |     <td><code>removeEventListener</code></td>
115 |     <td>
116 |       <p><strong>Parameters:</strong></p>
117 |       <ul>
118 |         <li><em>type</em>: <code>string</code></li>
119 |         <li><em>listener</em>: <code>function(Event)</code></li>
120 |       </ul>
121 |       <p>Removes a function from the current list of listeners for the passed event type. <em>(Note: at the moment only the "statechange" event type is supported.)</em></p>
122 |     </td>
123 |   </tr>
124 |   <tr valign="top">
125 |     <td><code>addUnsavedChanges</code></td>
126 |     <td>
127 |       <p><strong>Parameters:</strong></p>
128 |       <ul>
129 |         <li><em>id</em>: <code>Object|Symbol</code></li>
130 |       </ul>
131 |       <p>Adds an item to an internal pending-changes stack. Calling this method adds a generic <code>beforeunload</code> listener to the window (if one isn't already added).</p>
132 |       <p>The argument passed should be unique to this state, as it can only be removed by passing the same argument to <code>removeUnsavedChanges()</code>.
133 |       </p>
134 |     </td>
135 |   </tr>
136 |   <tr valign="top">
137 |     <td><code>removeUnsavedChanges</code></td>
138 |     <td>
139 |       <p><strong>Parameters:</strong></p>
140 |       <ul>
141 |         <li><em>id</em>: <code>Object|Symbol</code></li>
142 |       </ul>
143 |       <p>Removes an item matching the passed argument from an internal pending-changes stack. If the stack is empty, the generic <code>beforeunload</code> listener is removed from the window.</p>
144 |     </td>
145 |   </tr>
146 | </table>
147 | 
148 | ### Events
149 | 
150 | <table>
151 |   <tr valign="top">
152 |     <th align="left">Name</th>
153 |     <th align="left">Description</th>
154 |   </tr>
155 |   <tr valign="top">
156 |     <td><code>statechange</code></td>
157 |     <td>
158 |       <p><strong>Properties:</strong></p>
159 |       <ul>
160 |         <li><em>newState</em>: <code>string</code> The current lifecycle state the page just transitioned to.</li>
161 |         <li><em>oldState</em>: <code>string</code> The previous lifecycle state the page just transitioned from.</li>
162 |         <li><em>originalEvent</em>: <code>Event</code> the DOM event that triggered the state change.</li>
163 |       </ul>
164 |       <p>The <code>statechange</code> event is fired whenever the page's lifecycle state changes.</p>
165 |     </td>
166 |   </tr>
167 | </table>
168 | 
169 | 
170 | ## Browser Support
171 | 
172 | <table>
173 |   <tr>
174 |     <td align="center">
175 |       <img src="https://raw.githubusercontent.com/alrra/browser-logos/39.2.2/src/chrome/chrome_48x48.png" alt="Chrome"><br>
176 |       ✔
177 |     </td>
178 |     <td align="center">
179 |       <img src="https://raw.githubusercontent.com/alrra/browser-logos/39.2.2/src/firefox/firefox_48x48.png" alt="Firefox"><br>
180 |       ✔
181 |     </td>
182 |     <td align="center">
183 |       <img src="https://raw.githubusercontent.com/alrra/browser-logos/39.2.2/src/safari/safari_48x48.png" alt="Safari"><br>
184 |       ✔
185 |     </td>
186 |     <td align="center">
187 |       <img src="https://raw.githubusercontent.com/alrra/browser-logos/39.2.2/src/edge/edge_48x48.png" alt="Edge"><br>
188 |       ✔
189 |     </td>
190 |     <td align="center">
191 |       <img src="https://raw.githubusercontent.com/alrra/browser-logos/39.2.2/src/archive/internet-explorer_9-11/internet-explorer_9-11_48x48.png" alt="Internet Explorer"><br>
192 |       9+
193 |     </td>
194 |     <td align="center">
195 |       <img src="https://raw.githubusercontent.com/alrra/browser-logos/39.2.2/src/opera/opera_48x48.png" alt="Opera"><br>
196 |       ✔
197 |     </td>
198 |   </tr>
199 | </table>
200 | 
201 | PageLifecycle.js has been tested and known to work in the above browsers.
202 | 


--------------------------------------------------------------------------------
/src/Lifecycle.mjs:
--------------------------------------------------------------------------------
  1 | /*
  2 |  Copyright 2018 Google Inc. All Rights Reserved.
  3 |  Licensed under the Apache License, Version 2.0 (the "License");
  4 |  you may not use this file except in compliance with the License.
  5 |  You may obtain a copy of the License at
  6 | 
  7 |      http://www.apache.org/licenses/LICENSE-2.0
  8 | 
  9 |  Unless required by applicable law or agreed to in writing, software
 10 |  distributed under the License is distributed on an "AS IS" BASIS,
 11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 12 |  See the License for the specific language governing permissions and
 13 |  limitations under the License.
 14 | */
 15 | 
 16 | import EventTarget from './shims/EventTarget.mjs';
 17 | import StateChangeEvent from './StateChangeEvent.mjs';
 18 | 
 19 | const ACTIVE = 'active';
 20 | const PASSIVE = 'passive';
 21 | const HIDDEN = 'hidden';
 22 | const FROZEN = 'frozen';
 23 | // const DISCARDED = 'discarded'; Not used but show to completeness.
 24 | const TERMINATED = 'terminated';
 25 | 
 26 | // Detect Safari to work around Safari-specific bugs.
 27 | const IS_SAFARI = typeof safari === 'object' && safari.pushNotification;
 28 | 
 29 | const SUPPORTS_PAGE_TRANSITION_EVENTS = 'onpageshow' in self;
 30 | 
 31 | const EVENTS = [
 32 |   'focus',
 33 |   'blur',
 34 |   'visibilitychange',
 35 |   'freeze',
 36 |   'resume',
 37 |   'pageshow',
 38 |   // IE9-10 do not support the pagehide event, so we fall back to unload
 39 |   // Note: unload *MUST ONLY* be added conditionally, otherwise it will
 40 |   // prevent page navigation caching (a.k.a bfcache).
 41 |   SUPPORTS_PAGE_TRANSITION_EVENTS ? 'pagehide' : 'unload',
 42 | ];
 43 | 
 44 | /**
 45 |  * @param {!Event} evt
 46 |  * @return {string}
 47 |  */
 48 | const onbeforeunload = (evt) => {
 49 |   evt.preventDefault();
 50 |   return evt.returnValue = 'Are you sure?';
 51 | };
 52 | 
 53 | /**
 54 |  * Converts an array of states into an object where the state is the key
 55 |  * and the value is the index.
 56 |  * @param {!Array<string>} arr
 57 |  * @return {!Object}
 58 |  */
 59 | const toIndexedObject = (arr) => arr.reduce((acc, val, idx) => {
 60 |   acc[val] = idx;
 61 |   return acc;
 62 | }, {});
 63 | 
 64 | /**
 65 |  * @type {!Array<!Object>}
 66 |  */
 67 | const LEGAL_STATE_TRANSITIONS = [
 68 |   // The normal unload process (bfcache process is addressed above).
 69 |   [ACTIVE, PASSIVE, HIDDEN, TERMINATED],
 70 | 
 71 |   // An active page transitioning to frozen,
 72 |   // or an unloading page going into the bfcache.
 73 |   [ACTIVE, PASSIVE, HIDDEN, FROZEN],
 74 | 
 75 |   // A hidden page transitioning back to active.
 76 |   [HIDDEN, PASSIVE, ACTIVE],
 77 | 
 78 |   // A frozen page being resumed
 79 |   [FROZEN, HIDDEN],
 80 | 
 81 |   // A frozen (bfcached) page navigated back to
 82 |   // Note: [FROZEN, HIDDEN] can happen here, but it's already covered above.
 83 |   [FROZEN, ACTIVE],
 84 |   [FROZEN, PASSIVE],
 85 | ].map(toIndexedObject);
 86 | 
 87 | /**
 88 |  * Accepts a current state and a future state and returns an array of legal
 89 |  * state transition paths. This is needed to normalize behavior across browsers
 90 |  * since some browsers do not fire events in certain cases and thus skip
 91 |  * states.
 92 |  * @param {string} oldState
 93 |  * @param {string} newState
 94 |  * @return {!Array<string>}
 95 |  */
 96 | const getLegalStateTransitionPath = (oldState, newState) => {
 97 |   // We're intentionally not using for...of here so when we transpile to ES5
 98 |   // we don't need to include the Symbol polyfills.
 99 |   for (let order, i = 0; order = LEGAL_STATE_TRANSITIONS[i]; ++i) {
100 |     const oldIndex = order[oldState];
101 |     const newIndex = order[newState];
102 | 
103 |     if (oldIndex >= 0 &&
104 |         newIndex >= 0 &&
105 |         newIndex > oldIndex) {
106 |       // Differences greater than one should be reported
107 |       // because it means a state was skipped.
108 |       return Object.keys(order).slice(oldIndex, newIndex + 1);
109 |     }
110 |   }
111 |   return [];
112 |   // TODO(philipwalton): it shouldn't be possible to get here, but
113 |   // consider some kind of warning or call to action if it happens.
114 |   // console.warn(`Invalid state change detected: ${oldState} > ${newState}`);
115 | };
116 | 
117 | /**
118 |  * Returns the current state based on the document's visibility and
119 |  * in input focus states. Note this method is only used to determine
120 |  * active vs passive vs hidden states, as other states require listening
121 |  * for events.
122 |  * @return {string}
123 |  */
124 | const getCurrentState = () => {
125 |   if (document.visibilityState === HIDDEN) {
126 |     return HIDDEN;
127 |   }
128 |   if (document.hasFocus()) {
129 |     return ACTIVE;
130 |   }
131 |   return PASSIVE;
132 | };
133 | 
134 | /**
135 |  * Class definition for the exported, singleton lifecycle instance.
136 |  */
137 | export default class Lifecycle extends EventTarget {
138 |   /**
139 |    * Initializes state, state history, and adds event listeners to monitor
140 |    * state changes.
141 |    */
142 |   constructor() {
143 |     super();
144 | 
145 |     const state = getCurrentState();
146 | 
147 |     this._state = state;
148 |     this._unsavedChanges = [];
149 | 
150 |     // Bind the callback and add event listeners.
151 |     this._handleEvents = this._handleEvents.bind(this);
152 | 
153 |     // Add capturing events on window so they run immediately.
154 |     EVENTS.forEach((evt) => addEventListener(evt, this._handleEvents, true));
155 | 
156 |     // Safari does not reliably fire the `pagehide` or `visibilitychange`
157 |     // events when closing a tab, so we have to use `beforeunload` with a
158 |     // timeout to check whether the default action was prevented.
159 |     // - https://bugs.webkit.org/show_bug.cgi?id=151610
160 |     // - https://bugs.webkit.org/show_bug.cgi?id=151234
161 |     // NOTE: we only add this to Safari because adding it to Firefox would
162 |     // prevent the page from being eligible for bfcache.
163 |     if (IS_SAFARI) {
164 |       addEventListener('beforeunload', (evt) => {
165 |         this._safariBeforeUnloadTimeout = setTimeout(() => {
166 |           if (!(evt.defaultPrevented || evt.returnValue.length > 0)) {
167 |             this._dispatchChangesIfNeeded(evt, HIDDEN);
168 |           }
169 |         }, 0);
170 |       });
171 |     }
172 |   }
173 | 
174 |   /**
175 |    * @return {string}
176 |    */
177 |   get state() {
178 |     return this._state;
179 |   }
180 | 
181 |   /**
182 |    * Returns the value of document.wasDiscarded. This is arguably unnecessary
183 |    * but I think there's value in having the entire API in one place and
184 |    * consistent across browsers.
185 |    * @return {boolean}
186 |    */
187 |   get pageWasDiscarded() {
188 |     return document.wasDiscarded || false;
189 |   }
190 | 
191 |   /**
192 |    * @param {Symbol|Object} id A unique symbol or object identifying the
193 |    *.    pending state. This ID is required when removing the state later.
194 |    */
195 |   addUnsavedChanges(id) {
196 |     // Don't add duplicate state. Note: ideall this would be a set, but for
197 |     // better browser compatibility we're using an array.
198 |     if (!this._unsavedChanges.indexOf(id) > -1) {
199 |       // If this is the first state being added,
200 |       // also add a beforeunload listener.
201 |       if (this._unsavedChanges.length === 0) {
202 |         addEventListener('beforeunload', onbeforeunload);
203 |       }
204 |       this._unsavedChanges.push(id);
205 |     }
206 |   }
207 | 
208 |   /**
209 |    * @param {Symbol|Object} id A unique symbol or object identifying the
210 |    *.    pending state. This ID is required when removing the state later.
211 |    */
212 |   removeUnsavedChanges(id) {
213 |     const idIndex = this._unsavedChanges.indexOf(id);
214 | 
215 |     if (idIndex > -1) {
216 |       this._unsavedChanges.splice(idIndex, 1);
217 | 
218 |       // If there's no more pending state, remove the event listener.
219 |       if (this._unsavedChanges.length === 0) {
220 |         removeEventListener('beforeunload', onbeforeunload);
221 |       }
222 |     }
223 |   }
224 | 
225 |   /**
226 |    * @private
227 |    * @param {!Event} originalEvent
228 |    * @param {string} newState
229 |    */
230 |   _dispatchChangesIfNeeded(originalEvent, newState) {
231 |     if (newState !== this._state) {
232 |       const oldState = this._state;
233 |       const path = getLegalStateTransitionPath(oldState, newState);
234 | 
235 |       for (let i = 0; i < path.length - 1; ++i) {
236 |         const oldState = path[i];
237 |         const newState = path[i + 1];
238 | 
239 |         this._state = newState;
240 |         this.dispatchEvent(new StateChangeEvent('statechange', {
241 |           oldState,
242 |           newState,
243 |           originalEvent,
244 |         }));
245 |       }
246 |     }
247 |   }
248 | 
249 |   /**
250 |    * @private
251 |    * @param {!Event} evt
252 |    */
253 |   _handleEvents(evt) {
254 |     if (IS_SAFARI) {
255 |       clearTimeout(this._safariBeforeUnloadTimeout);
256 |     }
257 | 
258 |     switch (evt.type) {
259 |       case 'pageshow':
260 |       case 'resume':
261 |         this._dispatchChangesIfNeeded(evt, getCurrentState());
262 |         break;
263 |       case 'focus':
264 |         this._dispatchChangesIfNeeded(evt, ACTIVE);
265 |         break;
266 |       case 'blur':
267 |         // The `blur` event can fire while the page is being unloaded, so we
268 |         // only need to update the state if the current state is "active".
269 |         if (this._state === ACTIVE) {
270 |           this._dispatchChangesIfNeeded(evt, getCurrentState());
271 |         }
272 |         break;
273 |       case 'pagehide':
274 |       case 'unload':
275 |         this._dispatchChangesIfNeeded(evt, evt.persisted ? FROZEN : TERMINATED);
276 |         break;
277 |       case 'visibilitychange':
278 |         // The document's `visibilityState` will change to hidden  as the page
279 |         // is being unloaded, but in such cases the lifecycle state shouldn't
280 |         // change.
281 |         if (this._state !== FROZEN &&
282 |             this._state !== TERMINATED) {
283 |           this._dispatchChangesIfNeeded(evt, getCurrentState());
284 |         }
285 |         break;
286 |       case 'freeze':
287 |         this._dispatchChangesIfNeeded(evt, FROZEN);
288 |         break;
289 |     }
290 |   }
291 | }
292 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
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--------------------------------------------------------------------------------
/dist/lifecycle.native.mjs.map:
--------------------------------------------------------------------------------
1 | {"version":3,"file":"lifecycle.native.mjs","sources":["src/StateChangeEvent.mjs","src/Lifecycle.mjs","src/export.mjs"],"sourcesContent":["/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport Event from './shims/Event.mjs';\n\n/**\n * implements {IStateChangeEvent}\n */\nexport default class StateChangeEvent extends Event {\n  /**\n   * @param {string} type\n   * @param {!Object} initDict\n   */\n  constructor(type, initDict) {\n    super(type);\n    this.newState = initDict.newState;\n    this.oldState = initDict.oldState;\n    this.originalEvent = initDict.originalEvent;\n  }\n}\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport EventTarget from './shims/EventTarget.mjs';\nimport StateChangeEvent from './StateChangeEvent.mjs';\n\nconst ACTIVE = 'active';\nconst PASSIVE = 'passive';\nconst HIDDEN = 'hidden';\nconst FROZEN = 'frozen';\n// const DISCARDED = 'discarded'; Not used but show to completeness.\nconst TERMINATED = 'terminated';\n\n// Detect Safari to work around Safari-specific bugs.\nconst IS_SAFARI = typeof safari === 'object' && safari.pushNotification;\n\nconst SUPPORTS_PAGE_TRANSITION_EVENTS = 'onpageshow' in self;\n\nconst EVENTS = [\n  'focus',\n  'blur',\n  'visibilitychange',\n  'freeze',\n  'resume',\n  'pageshow',\n  // IE9-10 do not support the pagehide event, so we fall back to unload\n  // Note: unload *MUST ONLY* be added conditionally, otherwise it will\n  // prevent page navigation caching (a.k.a bfcache).\n  SUPPORTS_PAGE_TRANSITION_EVENTS ? 'pagehide' : 'unload',\n];\n\n/**\n * @param {!Event} evt\n * @return {string}\n */\nconst onbeforeunload = (evt) => {\n  evt.preventDefault();\n  return evt.returnValue = 'Are you sure?';\n};\n\n/**\n * Converts an array of states into an object where the state is the key\n * and the value is the index.\n * @param {!Array<string>} arr\n * @return {!Object}\n */\nconst toIndexedObject = (arr) => arr.reduce((acc, val, idx) => {\n  acc[val] = idx;\n  return acc;\n}, {});\n\n/**\n * @type {!Array<!Object>}\n */\nconst LEGAL_STATE_TRANSITIONS = [\n  // The normal unload process (bfcache process is addressed above).\n  [ACTIVE, PASSIVE, HIDDEN, TERMINATED],\n\n  // An active page transitioning to frozen,\n  // or an unloading page going into the bfcache.\n  [ACTIVE, PASSIVE, HIDDEN, FROZEN],\n\n  // A hidden page transitioning back to active.\n  [HIDDEN, PASSIVE, ACTIVE],\n\n  // A frozen page being resumed\n  [FROZEN, HIDDEN],\n\n  // A frozen (bfcached) page navigated back to\n  // Note: [FROZEN, HIDDEN] can happen here, but it's already covered above.\n  [FROZEN, ACTIVE],\n  [FROZEN, PASSIVE],\n].map(toIndexedObject);\n\n/**\n * Accepts a current state and a future state and returns an array of legal\n * state transition paths. This is needed to normalize behavior across browsers\n * since some browsers do not fire events in certain cases and thus skip\n * states.\n * @param {string} oldState\n * @param {string} newState\n * @return {!Array<string>}\n */\nconst getLegalStateTransitionPath = (oldState, newState) => {\n  // We're intentionally not using for...of here so when we transpile to ES5\n  // we don't need to include the Symbol polyfills.\n  for (let order, i = 0; order = LEGAL_STATE_TRANSITIONS[i]; ++i) {\n    const oldIndex = order[oldState];\n    const newIndex = order[newState];\n\n    if (oldIndex >= 0 &&\n        newIndex >= 0 &&\n        newIndex > oldIndex) {\n      // Differences greater than one should be reported\n      // because it means a state was skipped.\n      return Object.keys(order).slice(oldIndex, newIndex + 1);\n    }\n  }\n  return [];\n  // TODO(philipwalton): it shouldn't be possible to get here, but\n  // consider some kind of warning or call to action if it happens.\n  // console.warn(`Invalid state change detected: ${oldState} > ${newState}`);\n};\n\n/**\n * Returns the current state based on the document's visibility and\n * in input focus states. Note this method is only used to determine\n * active vs passive vs hidden states, as other states require listening\n * for events.\n * @return {string}\n */\nconst getCurrentState = () => {\n  if (document.visibilityState === HIDDEN) {\n    return HIDDEN;\n  }\n  if (document.hasFocus()) {\n    return ACTIVE;\n  }\n  return PASSIVE;\n};\n\n/**\n * Class definition for the exported, singleton lifecycle instance.\n */\nexport default class Lifecycle extends EventTarget {\n  /**\n   * Initializes state, state history, and adds event listeners to monitor\n   * state changes.\n   */\n  constructor() {\n    super();\n\n    const state = getCurrentState();\n\n    this._state = state;\n    this._unsavedChanges = [];\n\n    // Bind the callback and add event listeners.\n    this._handleEvents = this._handleEvents.bind(this);\n\n    // Add capturing events on window so they run immediately.\n    EVENTS.forEach((evt) => addEventListener(evt, this._handleEvents, true));\n\n    // Safari does not reliably fire the `pagehide` or `visibilitychange`\n    // events when closing a tab, so we have to use `beforeunload` with a\n    // timeout to check whether the default action was prevented.\n    // NOTE: we only add this to Safari because adding it to Firefox would\n    // prevent the page from being eligible for bfcache.\n    if (IS_SAFARI) {\n      addEventListener('beforeunload', (evt) => {\n        this._safariBeforeUnloadTimeout = setTimeout(() => {\n          if (!(evt.defaultPrevented || evt.returnValue.length > 0)) {\n            this._dispatchChangesIfNeeded(evt, HIDDEN);\n          }\n        }, 0);\n      });\n    }\n  }\n\n  /**\n   * @return {string}\n   */\n  get state() {\n    return this._state;\n  }\n\n  /**\n   * Returns the value of document.wasDiscarded. This is arguably unnecessary\n   * but I think there's value in having the entire API in one place and\n   * consistent across browsers.\n   * @return {boolean}\n   */\n  get pageWasDiscarded() {\n    return document.wasDiscarded || false;\n  }\n\n  /**\n   * @param {Symbol|Object} id A unique symbol or object identifying the\n   *.    pending state. This ID is required when removing the state later.\n   */\n  addUnsavedChanges(id) {\n    // Don't add duplicate state. Note: ideall this would be a set, but for\n    // better browser compatibility we're using an array.\n    if (!this._unsavedChanges.indexOf(id) > -1) {\n      // If this is the first state being added,\n      // also add a beforeunload listener.\n      if (this._unsavedChanges.length === 0) {\n        addEventListener('beforeunload', onbeforeunload);\n      }\n      this._unsavedChanges.push(id);\n    }\n  }\n\n  /**\n   * @param {Symbol|Object} id A unique symbol or object identifying the\n   *.    pending state. This ID is required when removing the state later.\n   */\n  removeUnsavedChanges(id) {\n    const idIndex = this._unsavedChanges.indexOf(id);\n\n    if (idIndex > -1) {\n      this._unsavedChanges.splice(idIndex, 1);\n\n      // If there's no more pending state, remove the event listener.\n      if (this._unsavedChanges.length === 0) {\n        removeEventListener('beforeunload', onbeforeunload);\n      }\n    }\n  }\n\n  /**\n   * @private\n   * @param {!Event} originalEvent\n   * @param {string} newState\n   */\n  _dispatchChangesIfNeeded(originalEvent, newState) {\n    if (newState !== this._state) {\n      const oldState = this._state;\n      const path = getLegalStateTransitionPath(oldState, newState);\n\n      for (let i = 0; i < path.length - 1; ++i) {\n        const oldState = path[i];\n        const newState = path[i + 1];\n\n        this._state = newState;\n        this.dispatchEvent(new StateChangeEvent('statechange', {\n          oldState,\n          newState,\n          originalEvent,\n        }));\n      }\n    }\n  }\n\n  /**\n   * @private\n   * @param {!Event} evt\n   */\n  _handleEvents(evt) {\n    if (IS_SAFARI) {\n      clearTimeout(this._safariBeforeUnloadTimeout);\n    }\n\n    switch (evt.type) {\n      case 'pageshow':\n      case 'resume':\n        this._dispatchChangesIfNeeded(evt, getCurrentState());\n        break;\n      case 'focus':\n        this._dispatchChangesIfNeeded(evt, ACTIVE);\n        break;\n      case 'blur':\n        // The `blur` event can fire while the page is being unloaded, so we\n        // only need to update the state if the current state is \"active\".\n        if (this._state === ACTIVE) {\n          this._dispatchChangesIfNeeded(evt, getCurrentState());\n        }\n        break;\n      case 'pagehide':\n      case 'unload':\n        this._dispatchChangesIfNeeded(evt, evt.persisted ? FROZEN : TERMINATED);\n        break;\n      case 'visibilitychange':\n        // The document's `visibilityState` will change to hidden  as the page\n        // is being unloaded, but in such cases the lifecycle state shouldn't\n        // change.\n        if (this._state !== FROZEN &&\n            this._state !== TERMINATED) {\n          this._dispatchChangesIfNeeded(evt, getCurrentState());\n        }\n        break;\n      case 'freeze':\n        this._dispatchChangesIfNeeded(evt, FROZEN);\n        break;\n    }\n  }\n}\n","/*\n Copyright 2018 Google Inc. 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1 | {"version":3,"file":"lifecycle.es5.js","sources":["src/shims/support.mjs","src/shims/EventTarget.mjs","src/shims/Event.mjs","src/StateChangeEvent.mjs","src/Lifecycle.mjs","src/export.mjs"],"sourcesContent":["/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nlet supportsConstructableEventTarget;\n\ntry {\n  new EventTarget();\n\n  // When transpiled with babel and rollup, the `IS_CODE_TRANSPILED` constant\n  // is replaced with the boolean `true`, so this statement will always\n  // evaluate to `false`. When not transpiled, it will be true.\n  supportsConstructableEventTarget = typeof IS_CODE_TRANSPILED === 'undefined';\n} catch (err) {\n  supportsConstructableEventTarget = false;\n}\n\nexport {supportsConstructableEventTarget};\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport {supportsConstructableEventTarget} from './support.mjs';\n\n\n/**\n * A minimal EventTarget class shim.\n * This is used if the browser doesn't natively support constructable\n * EventTarget objects.\n */\nclass EventTargetShim {\n  /**\n   * Creates the event registry.\n   */\n  constructor() {\n    this._registry = {};\n  }\n\n  /**\n   * @param {string} type\n   * @param {EventListener|function(!Event):(boolean|undefined)} listener\n   * @param {(boolean|!AddEventListenerOptions)=} opts\n   * @return {undefined}\n   * @see https://dom.spec.whatwg.org/#dom-eventtarget-addeventlistener\n   */\n  addEventListener(type, listener, opts = false) {\n    this._getRegistry(type).push(listener);\n  }\n\n  /**\n   * @param {string} type\n   * @param {EventListener|function(!Event):(boolean|undefined)} listener\n   * @param {(boolean|!EventListenerOptions)=} opts\n   * @return {undefined}\n   * @see https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener\n   */\n  removeEventListener(type, listener, opts = false) {\n    const typeRegistry = this._getRegistry(type);\n    const handlerIndex = typeRegistry.indexOf(listener);\n    if (handlerIndex > -1) {\n      typeRegistry.splice(handlerIndex, 1);\n    }\n  }\n\n  /**\n   * @param {!Event|!EventShim} evt\n   * @return {boolean}\n   * @see https://dom.spec.whatwg.org/#dom-eventtarget-dispatchevent\n   */\n  dispatchEvent(evt) {\n    // Set the target then freeze the event object to prevent modification.\n    evt.target = this;\n    Object.freeze(evt);\n\n    this._getRegistry(evt.type).forEach((listener) => listener(evt));\n    return true;\n  }\n\n  /**\n   * Returns an array of handlers associated with the passed event type.\n   * If no handlers have been registered, an empty array is returned.\n   * @private\n   * @param {string} type The event type.\n   * @return {!Array} An array of handler functions.\n   */\n  _getRegistry(type) {\n    return this._registry[type] = (this._registry[type] || []);\n  }\n}\n\nexport default supportsConstructableEventTarget ? EventTarget : EventTargetShim;\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport {supportsConstructableEventTarget} from './support.mjs';\n\n/**\n * A minimal Event class shim.\n * This is used if the browser doesn't natively support constructable\n * EventTarget objects.\n */\nclass EventShim {\n  /**\n   * @param {string} type\n   */\n  constructor(type) {\n    this.type = type;\n  }\n}\n\nexport default supportsConstructableEventTarget ? Event : EventShim;\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport Event from './shims/Event.mjs';\n\n/**\n * implements {IStateChangeEvent}\n */\nexport default class StateChangeEvent extends Event {\n  /**\n   * @param {string} type\n   * @param {!Object} initDict\n   */\n  constructor(type, initDict) {\n    super(type);\n    this.newState = initDict.newState;\n    this.oldState = initDict.oldState;\n    this.originalEvent = initDict.originalEvent;\n  }\n}\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport EventTarget from './shims/EventTarget.mjs';\nimport StateChangeEvent from './StateChangeEvent.mjs';\n\nconst ACTIVE = 'active';\nconst PASSIVE = 'passive';\nconst HIDDEN = 'hidden';\nconst FROZEN = 'frozen';\n// const DISCARDED = 'discarded'; Not used but show to completeness.\nconst TERMINATED = 'terminated';\n\n// Detect Safari to work around Safari-specific bugs.\nconst IS_SAFARI = typeof safari === 'object' && safari.pushNotification;\n\nconst SUPPORTS_PAGE_TRANSITION_EVENTS = 'onpageshow' in self;\n\nconst EVENTS = [\n  'focus',\n  'blur',\n  'visibilitychange',\n  'freeze',\n  'resume',\n  'pageshow',\n  // IE9-10 do not support the pagehide event, so we fall back to unload\n  // Note: unload *MUST ONLY* be added conditionally, otherwise it will\n  // prevent page navigation caching (a.k.a bfcache).\n  SUPPORTS_PAGE_TRANSITION_EVENTS ? 'pagehide' : 'unload',\n];\n\n/**\n * @param {!Event} evt\n * @return {string}\n */\nconst onbeforeunload = (evt) => {\n  evt.preventDefault();\n  return evt.returnValue = 'Are you sure?';\n};\n\n/**\n * Converts an array of states into an object where the state is the key\n * and the value is the index.\n * @param {!Array<string>} arr\n * @return {!Object}\n */\nconst toIndexedObject = (arr) => arr.reduce((acc, val, idx) => {\n  acc[val] = idx;\n  return acc;\n}, {});\n\n/**\n * @type {!Array<!Object>}\n */\nconst LEGAL_STATE_TRANSITIONS = [\n  // The normal unload process (bfcache process is addressed above).\n  [ACTIVE, PASSIVE, HIDDEN, TERMINATED],\n\n  // An active page transitioning to frozen,\n  // or an unloading page going into the bfcache.\n  [ACTIVE, PASSIVE, HIDDEN, FROZEN],\n\n  // A hidden page transitioning back to active.\n  [HIDDEN, PASSIVE, ACTIVE],\n\n  // A frozen page being resumed\n  [FROZEN, HIDDEN],\n\n  // A frozen (bfcached) page navigated back to\n  // Note: [FROZEN, HIDDEN] can happen here, but it's already covered above.\n  [FROZEN, ACTIVE],\n  [FROZEN, PASSIVE],\n].map(toIndexedObject);\n\n/**\n * Accepts a current state and a future state and returns an array of legal\n * state transition paths. This is needed to normalize behavior across browsers\n * since some browsers do not fire events in certain cases and thus skip\n * states.\n * @param {string} oldState\n * @param {string} newState\n * @return {!Array<string>}\n */\nconst getLegalStateTransitionPath = (oldState, newState) => {\n  // We're intentionally not using for...of here so when we transpile to ES5\n  // we don't need to include the Symbol polyfills.\n  for (let order, i = 0; order = LEGAL_STATE_TRANSITIONS[i]; ++i) {\n    const oldIndex = order[oldState];\n    const newIndex = order[newState];\n\n    if (oldIndex >= 0 &&\n        newIndex >= 0 &&\n        newIndex > oldIndex) {\n      // Differences greater than one should be reported\n      // because it means a state was skipped.\n      return Object.keys(order).slice(oldIndex, newIndex + 1);\n    }\n  }\n  return [];\n  // TODO(philipwalton): it shouldn't be possible to get here, but\n  // consider some kind of warning or call to action if it happens.\n  // console.warn(`Invalid state change detected: ${oldState} > ${newState}`);\n};\n\n/**\n * Returns the current state based on the document's visibility and\n * in input focus states. Note this method is only used to determine\n * active vs passive vs hidden states, as other states require listening\n * for events.\n * @return {string}\n */\nconst getCurrentState = () => {\n  if (document.visibilityState === HIDDEN) {\n    return HIDDEN;\n  }\n  if (document.hasFocus()) {\n    return ACTIVE;\n  }\n  return PASSIVE;\n};\n\n/**\n * Class definition for the exported, singleton lifecycle instance.\n */\nexport default class Lifecycle extends EventTarget {\n  /**\n   * Initializes state, state history, and adds event listeners to monitor\n   * state changes.\n   */\n  constructor() {\n    super();\n\n    const state = getCurrentState();\n\n    this._state = state;\n    this._unsavedChanges = [];\n\n    // Bind the callback and add event listeners.\n    this._handleEvents = this._handleEvents.bind(this);\n\n    // Add capturing events on window so they run immediately.\n    EVENTS.forEach((evt) => addEventListener(evt, this._handleEvents, true));\n\n    // Safari does not reliably fire the `pagehide` or `visibilitychange`\n    // events when closing a tab, so we have to use `beforeunload` with a\n    // timeout to check whether the default action was prevented.\n    // NOTE: we only add this to Safari because adding it to Firefox would\n    // prevent the page from being eligible for bfcache.\n    if (IS_SAFARI) {\n      addEventListener('beforeunload', (evt) => {\n        this._safariBeforeUnloadTimeout = setTimeout(() => {\n          if (!(evt.defaultPrevented || evt.returnValue.length > 0)) {\n            this._dispatchChangesIfNeeded(evt, HIDDEN);\n          }\n        }, 0);\n      });\n    }\n  }\n\n  /**\n   * @return {string}\n   */\n  get state() {\n    return this._state;\n  }\n\n  /**\n   * Returns the value of document.wasDiscarded. This is arguably unnecessary\n   * but I think there's value in having the entire API in one place and\n   * consistent across browsers.\n   * @return {boolean}\n   */\n  get pageWasDiscarded() {\n    return document.wasDiscarded || false;\n  }\n\n  /**\n   * @param {Symbol|Object} id A unique symbol or object identifying the\n   *.    pending state. This ID is required when removing the state later.\n   */\n  addUnsavedChanges(id) {\n    // Don't add duplicate state. Note: ideall this would be a set, but for\n    // better browser compatibility we're using an array.\n    if (!this._unsavedChanges.indexOf(id) > -1) {\n      // If this is the first state being added,\n      // also add a beforeunload listener.\n      if (this._unsavedChanges.length === 0) {\n        addEventListener('beforeunload', onbeforeunload);\n      }\n      this._unsavedChanges.push(id);\n    }\n  }\n\n  /**\n   * @param {Symbol|Object} id A unique symbol or object identifying the\n   *.    pending state. This ID is required when removing the state later.\n   */\n  removeUnsavedChanges(id) {\n    const idIndex = this._unsavedChanges.indexOf(id);\n\n    if (idIndex > -1) {\n      this._unsavedChanges.splice(idIndex, 1);\n\n      // If there's no more pending state, remove the event listener.\n      if (this._unsavedChanges.length === 0) {\n        removeEventListener('beforeunload', onbeforeunload);\n      }\n    }\n  }\n\n  /**\n   * @private\n   * @param {!Event} originalEvent\n   * @param {string} newState\n   */\n  _dispatchChangesIfNeeded(originalEvent, newState) {\n    if (newState !== this._state) {\n      const oldState = this._state;\n      const path = getLegalStateTransitionPath(oldState, newState);\n\n      for (let i = 0; i < path.length - 1; ++i) {\n        const oldState = path[i];\n        const newState = path[i + 1];\n\n        this._state = newState;\n        this.dispatchEvent(new StateChangeEvent('statechange', {\n          oldState,\n          newState,\n          originalEvent,\n        }));\n      }\n    }\n  }\n\n  /**\n   * @private\n   * @param {!Event} evt\n   */\n  _handleEvents(evt) {\n    if (IS_SAFARI) {\n      clearTimeout(this._safariBeforeUnloadTimeout);\n    }\n\n    switch (evt.type) {\n      case 'pageshow':\n      case 'resume':\n        this._dispatchChangesIfNeeded(evt, getCurrentState());\n        break;\n      case 'focus':\n        this._dispatchChangesIfNeeded(evt, ACTIVE);\n        break;\n      case 'blur':\n        // The `blur` event can fire while the page is being unloaded, so we\n        // only need to update the state if the current state is \"active\".\n        if (this._state === ACTIVE) {\n          this._dispatchChangesIfNeeded(evt, getCurrentState());\n        }\n        break;\n      case 'pagehide':\n      case 'unload':\n        this._dispatchChangesIfNeeded(evt, evt.persisted ? FROZEN : TERMINATED);\n        break;\n      case 'visibilitychange':\n        // The document's `visibilityState` will change to hidden  as the page\n        // is being unloaded, but in such cases the lifecycle state shouldn't\n        // change.\n        if (this._state !== FROZEN &&\n            this._state !== TERMINATED) {\n          this._dispatchChangesIfNeeded(evt, getCurrentState());\n        }\n        break;\n      case 'freeze':\n        this._dispatchChangesIfNeeded(evt, FROZEN);\n        break;\n    }\n  }\n}\n","/*\n Copyright 2018 Google Inc. 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1 | {"version":3,"file":"lifecycle.mjs","sources":["src/shims/support.mjs","src/shims/EventTarget.mjs","src/shims/Event.mjs","src/StateChangeEvent.mjs","src/Lifecycle.mjs","src/export.mjs"],"sourcesContent":["/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nlet supportsConstructableEventTarget;\n\ntry {\n  new EventTarget();\n\n  // When transpiled with babel and rollup, the `IS_CODE_TRANSPILED` constant\n  // is replaced with the boolean `true`, so this statement will always\n  // evaluate to `false`. When not transpiled, it will be true.\n  supportsConstructableEventTarget = typeof IS_CODE_TRANSPILED === 'undefined';\n} catch (err) {\n  supportsConstructableEventTarget = false;\n}\n\nexport {supportsConstructableEventTarget};\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport {supportsConstructableEventTarget} from './support.mjs';\n\n\n/**\n * A minimal EventTarget class shim.\n * This is used if the browser doesn't natively support constructable\n * EventTarget objects.\n */\nclass EventTargetShim {\n  /**\n   * Creates the event registry.\n   */\n  constructor() {\n    this._registry = {};\n  }\n\n  /**\n   * @param {string} type\n   * @param {EventListener|function(!Event):(boolean|undefined)} listener\n   * @param {(boolean|!AddEventListenerOptions)=} opts\n   * @return {undefined}\n   * @see https://dom.spec.whatwg.org/#dom-eventtarget-addeventlistener\n   */\n  addEventListener(type, listener, opts = false) {\n    this._getRegistry(type).push(listener);\n  }\n\n  /**\n   * @param {string} type\n   * @param {EventListener|function(!Event):(boolean|undefined)} listener\n   * @param {(boolean|!EventListenerOptions)=} opts\n   * @return {undefined}\n   * @see https://dom.spec.whatwg.org/#dom-eventtarget-removeeventlistener\n   */\n  removeEventListener(type, listener, opts = false) {\n    const typeRegistry = this._getRegistry(type);\n    const handlerIndex = typeRegistry.indexOf(listener);\n    if (handlerIndex > -1) {\n      typeRegistry.splice(handlerIndex, 1);\n    }\n  }\n\n  /**\n   * @param {!Event|!EventShim} evt\n   * @return {boolean}\n   * @see https://dom.spec.whatwg.org/#dom-eventtarget-dispatchevent\n   */\n  dispatchEvent(evt) {\n    // Set the target then freeze the event object to prevent modification.\n    evt.target = this;\n    Object.freeze(evt);\n\n    this._getRegistry(evt.type).forEach((listener) => listener(evt));\n    return true;\n  }\n\n  /**\n   * Returns an array of handlers associated with the passed event type.\n   * If no handlers have been registered, an empty array is returned.\n   * @private\n   * @param {string} type The event type.\n   * @return {!Array} An array of handler functions.\n   */\n  _getRegistry(type) {\n    return this._registry[type] = (this._registry[type] || []);\n  }\n}\n\nexport default supportsConstructableEventTarget ? EventTarget : EventTargetShim;\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport {supportsConstructableEventTarget} from './support.mjs';\n\n/**\n * A minimal Event class shim.\n * This is used if the browser doesn't natively support constructable\n * EventTarget objects.\n */\nclass EventShim {\n  /**\n   * @param {string} type\n   */\n  constructor(type) {\n    this.type = type;\n  }\n}\n\nexport default supportsConstructableEventTarget ? Event : EventShim;\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport Event from './shims/Event.mjs';\n\n/**\n * implements {IStateChangeEvent}\n */\nexport default class StateChangeEvent extends Event {\n  /**\n   * @param {string} type\n   * @param {!Object} initDict\n   */\n  constructor(type, initDict) {\n    super(type);\n    this.newState = initDict.newState;\n    this.oldState = initDict.oldState;\n    this.originalEvent = initDict.originalEvent;\n  }\n}\n","/*\n Copyright 2018 Google Inc. All Rights Reserved.\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n     http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License.\n*/\n\nimport EventTarget from './shims/EventTarget.mjs';\nimport StateChangeEvent from './StateChangeEvent.mjs';\n\nconst ACTIVE = 'active';\nconst PASSIVE = 'passive';\nconst HIDDEN = 'hidden';\nconst FROZEN = 'frozen';\n// const DISCARDED = 'discarded'; Not used but show to completeness.\nconst TERMINATED = 'terminated';\n\n// Detect Safari to work around Safari-specific bugs.\nconst IS_SAFARI = typeof safari === 'object' && safari.pushNotification;\n\nconst SUPPORTS_PAGE_TRANSITION_EVENTS = 'onpageshow' in self;\n\nconst EVENTS = [\n  'focus',\n  'blur',\n  'visibilitychange',\n  'freeze',\n  'resume',\n  'pageshow',\n  // IE9-10 do not support the pagehide event, so we fall back to unload\n  // Note: unload *MUST ONLY* be added conditionally, otherwise it will\n  // prevent page navigation caching (a.k.a bfcache).\n  SUPPORTS_PAGE_TRANSITION_EVENTS ? 'pagehide' : 'unload',\n];\n\n/**\n * @param {!Event} evt\n * @return {string}\n */\nconst onbeforeunload = (evt) => {\n  evt.preventDefault();\n  return evt.returnValue = 'Are you sure?';\n};\n\n/**\n * Converts an array of states into an object where the state is the key\n * and the value is the index.\n * @param {!Array<string>} arr\n * @return {!Object}\n */\nconst toIndexedObject = (arr) => arr.reduce((acc, val, idx) => {\n  acc[val] = idx;\n  return acc;\n}, {});\n\n/**\n * @type {!Array<!Object>}\n */\nconst LEGAL_STATE_TRANSITIONS = [\n  // The normal unload process (bfcache process is addressed above).\n  [ACTIVE, PASSIVE, HIDDEN, TERMINATED],\n\n  // An active page transitioning to frozen,\n  // or an unloading page going into the bfcache.\n  [ACTIVE, PASSIVE, HIDDEN, FROZEN],\n\n  // A hidden page transitioning back to active.\n  [HIDDEN, PASSIVE, ACTIVE],\n\n  // A frozen page being resumed\n  [FROZEN, HIDDEN],\n\n  // A frozen (bfcached) page navigated back to\n  // Note: [FROZEN, HIDDEN] can happen here, but it's already covered above.\n  [FROZEN, ACTIVE],\n  [FROZEN, PASSIVE],\n].map(toIndexedObject);\n\n/**\n * Accepts a current state and a future state and returns an array of legal\n * state transition paths. This is needed to normalize behavior across browsers\n * since some browsers do not fire events in certain cases and thus skip\n * states.\n * @param {string} oldState\n * @param {string} newState\n * @return {!Array<string>}\n */\nconst getLegalStateTransitionPath = (oldState, newState) => {\n  // We're intentionally not using for...of here so when we transpile to ES5\n  // we don't need to include the Symbol polyfills.\n  for (let order, i = 0; order = LEGAL_STATE_TRANSITIONS[i]; ++i) {\n    const oldIndex = order[oldState];\n    const newIndex = order[newState];\n\n    if (oldIndex >= 0 &&\n        newIndex >= 0 &&\n        newIndex > oldIndex) {\n      // Differences greater than one should be reported\n      // because it means a state was skipped.\n      return Object.keys(order).slice(oldIndex, newIndex + 1);\n    }\n  }\n  return [];\n  // TODO(philipwalton): it shouldn't be possible to get here, but\n  // consider some kind of warning or call to action if it happens.\n  // console.warn(`Invalid state change detected: ${oldState} > ${newState}`);\n};\n\n/**\n * Returns the current state based on the document's visibility and\n * in input focus states. Note this method is only used to determine\n * active vs passive vs hidden states, as other states require listening\n * for events.\n * @return {string}\n */\nconst getCurrentState = () => {\n  if (document.visibilityState === HIDDEN) {\n    return HIDDEN;\n  }\n  if (document.hasFocus()) {\n    return ACTIVE;\n  }\n  return PASSIVE;\n};\n\n/**\n * Class definition for the exported, singleton lifecycle instance.\n */\nexport default class Lifecycle extends EventTarget {\n  /**\n   * Initializes state, state history, and adds event listeners to monitor\n   * state changes.\n   */\n  constructor() {\n    super();\n\n    const state = getCurrentState();\n\n    this._state = state;\n    this._unsavedChanges = [];\n\n    // Bind the callback and add event listeners.\n    this._handleEvents = this._handleEvents.bind(this);\n\n    // Add capturing events on window so they run immediately.\n    EVENTS.forEach((evt) => addEventListener(evt, this._handleEvents, true));\n\n    // Safari does not reliably fire the `pagehide` or `visibilitychange`\n    // events when closing a tab, so we have to use `beforeunload` with a\n    // timeout to check whether the default action was prevented.\n    // NOTE: we only add this to Safari because adding it to Firefox would\n    // prevent the page from being eligible for bfcache.\n    if (IS_SAFARI) {\n      addEventListener('beforeunload', (evt) => {\n        this._safariBeforeUnloadTimeout = setTimeout(() => {\n          if (!(evt.defaultPrevented || evt.returnValue.length > 0)) {\n            this._dispatchChangesIfNeeded(evt, HIDDEN);\n          }\n        }, 0);\n      });\n    }\n  }\n\n  /**\n   * @return {string}\n   */\n  get state() {\n    return this._state;\n  }\n\n  /**\n   * Returns the value of document.wasDiscarded. This is arguably unnecessary\n   * but I think there's value in having the entire API in one place and\n   * consistent across browsers.\n   * @return {boolean}\n   */\n  get pageWasDiscarded() {\n    return document.wasDiscarded || false;\n  }\n\n  /**\n   * @param {Symbol|Object} id A unique symbol or object identifying the\n   *.    pending state. This ID is required when removing the state later.\n   */\n  addUnsavedChanges(id) {\n    // Don't add duplicate state. Note: ideall this would be a set, but for\n    // better browser compatibility we're using an array.\n    if (!this._unsavedChanges.indexOf(id) > -1) {\n      // If this is the first state being added,\n      // also add a beforeunload listener.\n      if (this._unsavedChanges.length === 0) {\n        addEventListener('beforeunload', onbeforeunload);\n      }\n      this._unsavedChanges.push(id);\n    }\n  }\n\n  /**\n   * @param {Symbol|Object} id A unique symbol or object identifying the\n   *.    pending state. This ID is required when removing the state later.\n   */\n  removeUnsavedChanges(id) {\n    const idIndex = this._unsavedChanges.indexOf(id);\n\n    if (idIndex > -1) {\n      this._unsavedChanges.splice(idIndex, 1);\n\n      // If there's no more pending state, remove the event listener.\n      if (this._unsavedChanges.length === 0) {\n        removeEventListener('beforeunload', onbeforeunload);\n      }\n    }\n  }\n\n  /**\n   * @private\n   * @param {!Event} originalEvent\n   * @param {string} newState\n   */\n  _dispatchChangesIfNeeded(originalEvent, newState) {\n    if (newState !== this._state) {\n      const oldState = this._state;\n      const path = getLegalStateTransitionPath(oldState, newState);\n\n      for (let i = 0; i < path.length - 1; ++i) {\n        const oldState = path[i];\n        const newState = path[i + 1];\n\n        this._state = newState;\n        this.dispatchEvent(new StateChangeEvent('statechange', {\n          oldState,\n          newState,\n          originalEvent,\n        }));\n      }\n    }\n  }\n\n  /**\n   * @private\n   * @param {!Event} evt\n   */\n  _handleEvents(evt) {\n    if (IS_SAFARI) {\n      clearTimeout(this._safariBeforeUnloadTimeout);\n    }\n\n    switch (evt.type) {\n      case 'pageshow':\n      case 'resume':\n        this._dispatchChangesIfNeeded(evt, getCurrentState());\n        break;\n      case 'focus':\n        this._dispatchChangesIfNeeded(evt, ACTIVE);\n        break;\n      case 'blur':\n        // The `blur` event can fire while the page is being unloaded, so we\n        // only need to update the state if the current state is \"active\".\n        if (this._state === ACTIVE) {\n          this._dispatchChangesIfNeeded(evt, getCurrentState());\n        }\n        break;\n      case 'pagehide':\n      case 'unload':\n        this._dispatchChangesIfNeeded(evt, evt.persisted ? FROZEN : TERMINATED);\n        break;\n      case 'visibilitychange':\n        // The document's `visibilityState` will change to hidden  as the page\n        // is being unloaded, but in such cases the lifecycle state shouldn't\n        // change.\n        if (this._state !== FROZEN &&\n            this._state !== TERMINATED) {\n          this._dispatchChangesIfNeeded(evt, getCurrentState());\n        }\n        break;\n      case 'freeze':\n        this._dispatchChangesIfNeeded(evt, FROZEN);\n        break;\n    }\n  }\n}\n","/*\n Copyright 2018 Google Inc. 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--------------------------------------------------------------------------------
/test/Lifecycle-test.mjs:
--------------------------------------------------------------------------------
  1 | /*
  2 |  Copyright 2018 Google Inc. All Rights Reserved.
  3 |  Licensed under the Apache License, Version 2.0 (the "License");
  4 |  you may not use this file except in compliance with the License.
  5 |  You may obtain a copy of the License at
  6 | 
  7 |      http://www.apache.org/licenses/LICENSE-2.0
  8 | 
  9 |  Unless required by applicable law or agreed to in writing, software
 10 |  distributed under the License is distributed on an "AS IS" BASIS,
 11 |  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 12 |  See the License for the specific language governing permissions and
 13 |  limitations under the License.
 14 | */
 15 | 
 16 | import Lifecycle from '../src/Lifecycle.mjs';
 17 | import NativeEventTargetOrEventTargetShim from '../src/shims/EventTarget.mjs';
 18 | import NativeEventOrEventShim from '../src/shims/Event.mjs';
 19 | 
 20 | // Detect Safari to work around Safari-specific bugs.
 21 | const IS_SAFARI = typeof safari === 'object' && safari.pushNotification;
 22 | const SUPPORTS_FREEZE_EVENT = 'onfreeze' in document;
 23 | const SUPPORTS_PAGE_TRANSITION_EVENTS = 'onpageshow' in self;
 24 | const SUPPORTS_PAGE_VISIBILITY = 'visibilityState' in document;
 25 | 
 26 | const sandbox = sinon.createSandbox();
 27 | 
 28 | /**
 29 |  * Dispatches an event, with optional props that should be added to the
 30 |  * event object. This method also only fires the event if the browser running
 31 |  * this could would actually fire it. This helps ensure the tests more
 32 |  * accurately reflect different scenarios the library could be run in.
 33 |  * @param {string} type The type of event to dispatch.
 34 |  * @param {Object=} props Additioal property/values to set on the event.
 35 |  */
 36 | const fireEvent = (type, props = {}) => {
 37 |   let event;
 38 | 
 39 |   // Don't fire events if the browser doesn't support them.
 40 |   switch (type) {
 41 |     case 'visibilitychange':
 42 |       if (!SUPPORTS_PAGE_VISIBILITY) return;
 43 |       break;
 44 |     case 'pageshow':
 45 |     case 'pagehide':
 46 |       if (!SUPPORTS_PAGE_TRANSITION_EVENTS) return;
 47 |       break;
 48 |     case 'freeze':
 49 |     case 'resume':
 50 |       if (!SUPPORTS_FREEZE_EVENT) return;
 51 |       break;
 52 |   }
 53 | 
 54 |   // Tries to create the event using a constructor, if that doesn't work,
 55 |   // falls back to `document.createEvent()`.
 56 |   try {
 57 |     event = new Event(type);
 58 |   } catch (err) {
 59 |     event = document.createEvent('Event');
 60 |     event.initEvent(type, false, false);
 61 |   }
 62 | 
 63 |   Object.keys(props).forEach((prop) => {
 64 |     Object.defineProperty(event, prop, {value: props[prop]});
 65 |   });
 66 | 
 67 |   self.dispatchEvent(event);
 68 | };
 69 | 
 70 | /**
 71 |  * A wrapper around `sinon.stub()` for properties that supports non-existent
 72 |  * own properties (sinon doesn't).
 73 |  * @param {!Object} obj
 74 |  * @param {string} prop
 75 |  * @param {*} value
 76 |  * @return {!Object}
 77 |  */
 78 | const stubProperty = (obj, prop, value) => {
 79 |   if (!obj.hasOwnProperty(prop)) {
 80 |     return {
 81 |       value: (value) => {
 82 |         Object.defineProperty(obj, prop, {value, configurable: true});
 83 |       },
 84 |     };
 85 |   } else {
 86 |     return sandbox.stub(obj, prop);
 87 |   }
 88 | };
 89 | 
 90 | /**
 91 |  * A wrapper around `sinon.stub()` for methods that automatically unstubs
 92 |  * an restubs a method if it's already been stubbed.
 93 |  * @param {!Object} obj
 94 |  * @param {string} method
 95 |  * @return {!Object}
 96 |  */
 97 | const stubMethod = (obj, method) => {
 98 |   if (obj[method].isSinonProxy) {
 99 |     obj[method].restore();
100 |   }
101 |   return sandbox.stub(obj, method);
102 | };
103 | 
104 | /**
105 |  * Stubs the properties and methods needed for Lifecycle to detect the
106 |  * correct state (either at instantiation time or after an event). Note that
107 |  * the frozen, terminated, and discarded states cannot be stubbed since
108 |  * they require an event to fire to be observable.
109 |  * @param {string} state
110 |  */
111 | const stubState = (state) => {
112 |   switch (state) {
113 |     case 'active':
114 |       stubProperty(document, 'visibilityState').value('visible');
115 |       stubMethod(document, 'hasFocus').returns(true);
116 |       break;
117 |     case 'passive':
118 |       stubProperty(document, 'visibilityState').value('visible');
119 |       stubMethod(document, 'hasFocus').returns(false);
120 |       break;
121 |     case 'hidden':
122 |       stubProperty(document, 'visibilityState').value('hidden');
123 |       stubMethod(document, 'hasFocus').returns(false);
124 |       break;
125 |   }
126 | };
127 | 
128 | /**
129 |  * Stubs the properties and methods needed for Lifecycle to detect the
130 |  * correct state (either at instantiation time or after an event). Note that
131 |  * the frozen, terminated, and discarded states cannot be stubbed since
132 |  * they require an event to fire to be observable.
133 |  * @param {string} oldState
134 |  * @param {string} newState
135 |  * @param {{bfcache: (string)}=} param3
136 |  *   - bfcache: true if the state change involves entering or leaving the
137 |  *.    page navigation cache (bfcache).
138 |  */
139 | const simulateStateChange = (oldState, newState, {bfcache} = {}) => {
140 |   stubState(newState);
141 | 
142 |   switch (newState) {
143 |     case 'active':
144 |       if (oldState === 'frozen') {
145 |         fireEvent('resume');
146 |         fireEvent('pageshow', {persisted: true});
147 |       }
148 |       fireEvent('focus');
149 |       break;
150 |     case 'passive':
151 |       if (oldState === 'active') {
152 |         fireEvent('blur');
153 |       }
154 |       if (oldState === 'hidden') {
155 |         fireEvent('visibilitychange');
156 |       }
157 |       if (oldState === 'frozen') {
158 |         fireEvent('resume');
159 |         fireEvent('pageshow', {persisted: true});
160 |       }
161 |       break;
162 |     case 'hidden':
163 |       if (oldState === 'passive') {
164 |         fireEvent('visibilitychange');
165 |       }
166 |       if (oldState === 'frozen') {
167 |         fireEvent('resume');
168 |         if (bfcache) {
169 |           fireEvent('pageshow', {persisted: true});
170 |         }
171 |       }
172 |       break;
173 |     case 'frozen':
174 |       if (bfcache) {
175 |         fireEvent('pagehide', {persisted: true});
176 |       }
177 |       fireEvent('freeze');
178 |       break;
179 |     case 'terminated':
180 |       fireEvent('pagehide');
181 |       fireEvent('unload'); // Needed for IE9-10
182 |       break;
183 |   }
184 | };
185 | 
186 | describe('Lifecycle', () => {
187 |   beforeEach(() => {
188 |     sandbox.restore();
189 |   });
190 | 
191 |   afterEach(() => {
192 |     sandbox.restore();
193 |   });
194 | 
195 |   describe(`constructor`, () => {
196 |     it(`extends EventTarget`, () => {
197 |       const lifecycle = new Lifecycle();
198 |       assert(lifecycle instanceof NativeEventTargetOrEventTargetShim);
199 |     });
200 | 
201 |     it(`adds capturing event listeners for all built-in lifecycle events`,
202 |         () => {
203 |       const spy = sandbox.spy(self, 'addEventListener');
204 | 
205 |       new Lifecycle();
206 | 
207 |       if (!IS_SAFARI) {
208 |         assert.equal(spy.callCount, 7);
209 |       } else {
210 |         // Safari requires a `beforeunload` listener to fix buggy behavior:
211 |         // https://github.com/GoogleChromeLabs/page-lifecycle/issues/2
212 |         assert.equal(spy.callCount, 8);
213 |         assert(spy.calledWith('beforeunload', sinon.match.func));
214 |       }
215 | 
216 |       assert(spy.calledWith('focus', sinon.match.func, true));
217 |       assert(spy.calledWith('blur', sinon.match.func, true));
218 |       assert(spy.calledWith('visibilitychange', sinon.match.func, true));
219 |       assert(spy.calledWith('freeze', sinon.match.func, true));
220 |       assert(spy.calledWith('resume', sinon.match.func, true));
221 |       if (SUPPORTS_PAGE_TRANSITION_EVENTS) {
222 |         assert(spy.calledWith('pageshow', sinon.match.func, true));
223 |         assert(spy.calledWith('pagehide', sinon.match.func, true));
224 |       } else {
225 |         assert(spy.calledWith('unload', sinon.match.func, true));
226 |       }
227 |     });
228 |   });
229 | 
230 |   describe(`get state`, () => {
231 |     it(`returns 'active' when the document is visible and has input focus`,
232 |         () => {
233 |       stubState('active');
234 |       const lifecycle = new Lifecycle();
235 | 
236 |       assert.equal(lifecycle.state, 'active');
237 |     });
238 | 
239 |     it(`returns 'passive' when the document visible and doesn't have input ` +
240 |         `focus`, () => {
241 |       stubState('passive');
242 |       const lifecycle = new Lifecycle();
243 | 
244 |       assert.equal(lifecycle.state, 'passive');
245 |     });
246 | 
247 |     it(`returns 'hidden' when the document is hidden and not frozen`, () => {
248 |       stubState('hidden');
249 |       const lifecycle = new Lifecycle();
250 | 
251 |       assert.equal(lifecycle.state, 'hidden');
252 |     });
253 | 
254 |     it(`returns 'frozen' if the freeze event has just fired`, () => {
255 |       if (SUPPORTS_FREEZE_EVENT) {
256 |         stubState('hidden');
257 |         const lifecycle = new Lifecycle();
258 | 
259 |         simulateStateChange('hidden', 'frozen');
260 | 
261 |         assert.equal(lifecycle.state, 'frozen');
262 |       }
263 |     });
264 | 
265 |     it(`returns 'frozen' if the page is entering the page navigation cache`,
266 |         () => {
267 |       if (SUPPORTS_PAGE_TRANSITION_EVENTS) {
268 |         stubState('hidden');
269 |         const lifecycle = new Lifecycle();
270 | 
271 |         simulateStateChange('hidden', 'frozen', {bfcache: true});
272 | 
273 |         assert.equal(lifecycle.state, 'frozen');
274 |       }
275 |     });
276 | 
277 |     it(`returns 'terminated' if the page is being unloaded`, () => {
278 |       stubState('hidden');
279 |       const lifecycle = new Lifecycle();
280 | 
281 |       simulateStateChange('hidden', 'terminated');
282 | 
283 |       assert.equal(lifecycle.state, 'terminated');
284 |     });
285 |   });
286 | 
287 |   describe(`get pageWasDiscarded`, () => {
288 |     it(`returns the value of document.wasDiscarded`, () => {
289 |       const lifecycle = new Lifecycle();
290 |       assert.equal(lifecycle.pageWasDiscarded, false);
291 | 
292 |       stubProperty(document, 'wasDiscarded').value(true);
293 |       assert.equal(lifecycle.pageWasDiscarded, true);
294 |     });
295 |   });
296 | 
297 |   describe(`addEventListener`, () => {
298 |     it(`adds a listener for statechange events`, () => {
299 |       stubState('active');
300 | 
301 |       const lifecycle = new Lifecycle();
302 |       const listener = sinon.spy();
303 |       lifecycle.addEventListener('statechange', listener);
304 | 
305 |       simulateStateChange('active', 'passive');
306 | 
307 |       assert.equal(listener.callCount, 1);
308 |       assert(listener.getCall(0).calledWith(sinon.match({
309 |         type: 'statechange',
310 |         oldState: 'active',
311 |         newState: 'passive',
312 |         target: lifecycle,
313 |       })));
314 |       assert(listener.getCall(0).args[0] instanceof NativeEventOrEventShim);
315 | 
316 |       simulateStateChange('passive', 'active');
317 | 
318 |       assert.equal(listener.callCount, 2);
319 |       assert(listener.getCall(1).calledWith(sinon.match({
320 |         type: 'statechange',
321 |         oldState: 'passive',
322 |         newState: 'active',
323 |         target: lifecycle,
324 |       })));
325 |       assert(listener.getCall(0).args[0] instanceof NativeEventOrEventShim);
326 |     });
327 | 
328 |     it(`tracks valid state change events from active to terminated`, () => {
329 |       stubState('active');
330 | 
331 |       const lifecycle = new Lifecycle();
332 |       const listener = sinon.spy();
333 |       lifecycle.addEventListener('statechange', listener);
334 | 
335 |       simulateStateChange('active', 'passive');
336 | 
337 |       assert(listener.calledOnce);
338 |       assert(listener.firstCall.calledWith(sinon.match({
339 |         oldState: 'active',
340 |         newState: 'passive',
341 |       })));
342 |       listener.resetHistory();
343 | 
344 |       simulateStateChange('passive', 'hidden');
345 |       simulateStateChange('hidden', 'terminated');
346 | 
347 |       assert(listener.calledTwice);
348 |       assert(listener.firstCall.calledWith(sinon.match({
349 |         oldState: 'passive',
350 |         newState: 'hidden',
351 |       })));
352 |       assert(listener.secondCall.calledWith(sinon.match({
353 |         oldState: 'hidden',
354 |         newState: 'terminated',
355 |       })));
356 |     });
357 | 
358 |     it(`tracks valid state change events from active to frozen, and back`,
359 |         () => {
360 |       stubState('active');
361 | 
362 |       const lifecycle = new Lifecycle();
363 |       const listener = sinon.spy();
364 |       lifecycle.addEventListener('statechange', listener);
365 | 
366 |       simulateStateChange('active', 'passive');
367 | 
368 |       assert(listener.calledOnce);
369 |       assert(listener.firstCall.calledWith(sinon.match({
370 |         oldState: 'active',
371 |         newState: 'passive',
372 |       })));
373 |       listener.resetHistory();
374 | 
375 |       if (SUPPORTS_PAGE_VISIBILITY) {
376 |         simulateStateChange('passive', 'hidden');
377 | 
378 |         assert(listener.calledOnce);
379 |         assert(listener.firstCall.calledWith(sinon.match({
380 |           oldState: 'passive',
381 |           newState: 'hidden',
382 |         })));
383 |         listener.resetHistory();
384 | 
385 |         if (SUPPORTS_FREEZE_EVENT) {
386 |           simulateStateChange('hidden', 'frozen');
387 |           simulateStateChange('frozen', 'hidden');
388 | 
389 |           assert(listener.calledTwice);
390 |           assert(listener.firstCall.calledWith(sinon.match({
391 |             oldState: 'hidden',
392 |             newState: 'frozen',
393 |           })));
394 |           assert(listener.secondCall.calledWith(sinon.match({
395 |             oldState: 'frozen',
396 |             newState: 'hidden',
397 |           })));
398 |           listener.resetHistory();
399 |         }
400 | 
401 |         simulateStateChange('hidden', 'passive');
402 | 
403 |         assert(listener.calledOnce);
404 |         assert(listener.firstCall.calledWith(sinon.match({
405 |           oldState: 'hidden',
406 |           newState: 'passive',
407 |         })));
408 |         listener.resetHistory();
409 |       }
410 | 
411 |       simulateStateChange('passive', 'active');
412 | 
413 |       assert(listener.calledOnce);
414 |       assert(listener.firstCall.calledWith(sinon.match({
415 |         oldState: 'passive',
416 |         newState: 'active',
417 |       })));
418 |     });
419 | 
420 |     it(`tracks valid state change events from active to frozen (in page cache)`,
421 |         () => {
422 |       stubState('active');
423 | 
424 |       const lifecycle = new Lifecycle();
425 |       const listener = sinon.spy();
426 |       lifecycle.addEventListener('statechange', listener);
427 | 
428 |       simulateStateChange('active', 'passive');
429 | 
430 |       assert(listener.calledOnce);
431 |       assert(listener.firstCall.calledWith(sinon.match({
432 |         oldState: 'active',
433 |         newState: 'passive',
434 |       })));
435 |       listener.resetHistory();
436 | 
437 |       if (SUPPORTS_PAGE_VISIBILITY) {
438 |         simulateStateChange('passive', 'hidden');
439 | 
440 |         assert(listener.calledOnce);
441 |         assert(listener.firstCall.calledWith(sinon.match({
442 |           oldState: 'passive',
443 |           newState: 'hidden',
444 |         })));
445 |         listener.resetHistory();
446 | 
447 |         if (SUPPORTS_PAGE_TRANSITION_EVENTS) {
448 |           simulateStateChange('hidden', 'frozen', {bfcache: true});
449 | 
450 |           assert(listener.calledOnce);
451 |           assert(listener.firstCall.calledWith(sinon.match({
452 |             oldState: 'hidden',
453 |             newState: 'frozen',
454 |           })));
455 |         }
456 |       }
457 |     });
458 | 
459 |     ['active', 'passive', 'hidden'].forEach((state) => {
460 |       it(`tracks valid state change events from frozen (in page cache) ` +
461 |           `to ${state}`, () => {
462 |         stubState('hidden');
463 |         const lifecycle = new Lifecycle();
464 |         simulateStateChange('hidden', 'frozen', {bfcache: true});
465 | 
466 |         if (SUPPORTS_PAGE_TRANSITION_EVENTS) {
467 |           const listener = sinon.spy();
468 |           lifecycle.addEventListener('statechange', listener);
469 | 
470 |           simulateStateChange('frozen', state, {bfcache: true});
471 | 
472 |           assert(listener.calledOnce);
473 |           assert(listener.firstCall.calledWith(sinon.match({
474 |             oldState: 'frozen',
475 |             newState: state,
476 |           })));
477 |         }
478 |       });
479 |     });
480 | 
481 |     // In Safari 12 (and below) you can switch tabs without getting a
482 |     // blur event. We need to ensure the passive state is still observed in
483 |     // this case.
484 |     it(`handles invalid changes from active to hidden, and back`, () => {
485 |       stubState('active');
486 | 
487 |       const lifecycle = new Lifecycle();
488 |       const listener = sinon.spy();
489 |       lifecycle.addEventListener('statechange', listener);
490 | 
491 |       if (SUPPORTS_PAGE_VISIBILITY) {
492 |         // Change the page's visibilityState to hidden without first firing a
493 |         // blur event.
494 |         stubMethod(document, 'hasFocus').returns(false);
495 |         stubProperty(document, 'visibilityState').value('hidden');
496 |         fireEvent('visibilitychange');
497 | 
498 |         assert.equal(listener.callCount, 2);
499 |         assert(listener.firstCall.calledWith(sinon.match({
500 |           oldState: 'active',
501 |           newState: 'passive',
502 |         })));
503 |         assert(listener.secondCall.calledWith(sinon.match({
504 |           oldState: 'passive',
505 |           newState: 'hidden',
506 |         })));
507 | 
508 |         listener.resetHistory();
509 | 
510 |         // Change the page's visibilityState back to visible and set document
511 |         // focus without first firing a focus event.
512 |         stubMethod(document, 'hasFocus').returns(true);
513 |         stubProperty(document, 'visibilityState').value('visible');
514 |         fireEvent('visibilitychange');
515 | 
516 |         assert.equal(listener.callCount, 2);
517 |         assert(listener.getCall(0).calledWith(sinon.match({
518 |           oldState: 'hidden',
519 |           newState: 'passive',
520 |         })));
521 |         assert(listener.getCall(1).calledWith(sinon.match({
522 |           oldState: 'passive',
523 |           newState: 'active',
524 |         })));
525 | 
526 |         listener.resetHistory();
527 |       }
528 |     });
529 | 
530 |     // In most browsers, navigating via an in-page link will not trigger a
531 |     // blur event (at least not right away). We need to ensure the passive
532 |     // state is still observed in this case.
533 |     // Chrome 67: pagehide > visibilitychange
534 |     // Firefox 60: pagehide > visibilitychange > blur
535 |     it(`handles invalid changes from active to frozen (page cache), and back`,
536 |         () => {
537 |       stubState('active');
538 | 
539 |       const lifecycle = new Lifecycle();
540 |       const listener = sinon.spy();
541 |       lifecycle.addEventListener('statechange', listener);
542 | 
543 |       if (SUPPORTS_PAGE_VISIBILITY && SUPPORTS_PAGE_TRANSITION_EVENTS) {
544 |         // Navigate away but put the page into the bfcache.
545 |         stubMethod(document, 'hasFocus').returns(false);
546 |         fireEvent('pagehide', {persisted: true});
547 | 
548 |         assert.equal(listener.callCount, 3);
549 |         assert(listener.getCall(0).calledWith(sinon.match({
550 |           oldState: 'active',
551 |           newState: 'passive',
552 |         })));
553 |         assert(listener.getCall(1).calledWith(sinon.match({
554 |           oldState: 'passive',
555 |           newState: 'hidden',
556 |         })));
557 |         assert(listener.getCall(2).calledWith(sinon.match({
558 |           oldState: 'hidden',
559 |           newState: 'frozen',
560 |         })));
561 | 
562 |         listener.resetHistory();
563 | 
564 |         // Navigate back, moving the page from frozen directly to active.
565 |         document.hasFocus.restore();
566 |         stubMethod(document, 'hasFocus').returns(true);
567 |         stubProperty(document, 'visibilityState').value('visible');
568 |         fireEvent('pageshow');
569 | 
570 |         assert.equal(listener.callCount, 1);
571 |         assert(listener.getCall(0).calledWith(sinon.match({
572 |           oldState: 'frozen',
573 |           newState: 'active',
574 |         })));
575 | 
576 |         listener.resetHistory();
577 |       }
578 |     });
579 | 
580 |     // All browsers (at this moment) fire the pagehide event before the
581 |     // visibilitychange event if the user is unloading an active tab.
582 |     // We need to ensure the state change happen in the right order.
583 |     // (Note: this behavior is current per-spec, but we're proposing an update
584 |     // https://github.com/w3c/page-visibility/issues/39)
585 |     it(`handles invalid changes from active to terminated`, () => {
586 |       stubState('active');
587 | 
588 |       const lifecycle = new Lifecycle();
589 |       const listener = sinon.spy();
590 |       lifecycle.addEventListener('statechange', listener);
591 | 
592 |       fireEvent('pagehide');
593 |       stubProperty(document, 'visibilityState').value('hidden');
594 |       fireEvent('visibilitychange');
595 |       fireEvent('unload');
596 | 
597 |       assert.equal(listener.callCount, 3);
598 |       assert(listener.getCall(0).calledWith(sinon.match({
599 |         oldState: 'active',
600 |         newState: 'passive',
601 |       })));
602 |       assert(listener.getCall(1).calledWith(sinon.match({
603 |         oldState: 'passive',
604 |         newState: 'hidden',
605 |       })));
606 |       assert(listener.getCall(2).calledWith(sinon.match({
607 |         oldState: 'hidden',
608 |         newState: 'terminated',
609 |       })));
610 |     });
611 | 
612 |     if (IS_SAFARI) {
613 |       it(`adds a beforeunload listener to detect missing pagehide events`,
614 |           (done) => {
615 |         stubState('active');
616 | 
617 |         const lifecycle = new Lifecycle();
618 |         const listener = sinon.spy();
619 |         lifecycle.addEventListener('statechange', listener);
620 | 
621 |         fireEvent('beforeunload');
622 |         setTimeout(() => {
623 |           assert.equal(listener.callCount, 2);
624 |           assert(listener.getCall(0).calledWith(sinon.match({
625 |             oldState: 'active',
626 |             newState: 'passive',
627 |           })));
628 |           assert(listener.getCall(1).calledWith(sinon.match({
629 |             oldState: 'passive',
630 |             newState: 'hidden',
631 |           })));
632 |           done();
633 |         }, 0);
634 |       });
635 | 
636 |       it(`accounts for the beforeunload listener being cancelled`, (done) => {
637 |         stubState('active');
638 | 
639 |         const lifecycle = new Lifecycle();
640 |         const listener = sinon.spy();
641 |         lifecycle.addEventListener('statechange', listener);
642 | 
643 |         fireEvent('beforeunload', {defaultPrevented: true});
644 |         fireEvent('beforeunload', {returnValue: '!'});
645 |         setTimeout(() => {
646 |           assert.equal(listener.callCount, 0);
647 |           done();
648 |         }, 0);
649 |       });
650 | 
651 |       it(`accounts for other events firing before the beforeunload timeout`,
652 |           (done) => {
653 |         stubState('active');
654 | 
655 |         const lifecycle = new Lifecycle();
656 |         const listener = sinon.spy();
657 |         lifecycle.addEventListener('statechange', listener);
658 | 
659 |         // Schedule a timeout to fire the pagehide and pageshow events
660 |         // to ensure that receiving other events cancels the logic about
661 |         // to be performed by the beforeunload listener.
662 |         setTimeout(() => {
663 |           fireEvent('pagehide', {persisted: true});
664 |           fireEvent('pageshow', {persisted: true});
665 |         }, 0);
666 | 
667 |         fireEvent('beforeunload');
668 |         setTimeout(() => {
669 |           assert.equal(listener.callCount, 4);
670 |           assert(listener.getCall(0).calledWith(sinon.match({
671 |             oldState: 'active',
672 |             newState: 'passive',
673 |             originalEvent: sinon.match({type: 'pagehide'}),
674 |           })));
675 |           assert(listener.getCall(1).calledWith(sinon.match({
676 |             oldState: 'passive',
677 |             newState: 'hidden',
678 |             originalEvent: sinon.match({type: 'pagehide'}),
679 |           })));
680 |           assert(listener.getCall(2).calledWith(sinon.match({
681 |             oldState: 'hidden',
682 |             newState: 'frozen',
683 |             originalEvent: sinon.match({type: 'pagehide'}),
684 |           })));
685 |           assert(listener.getCall(3).calledWith(sinon.match({
686 |             oldState: 'frozen',
687 |             newState: 'active',
688 |             originalEvent: sinon.match({type: 'pageshow'}),
689 |           })));
690 |           done();
691 |         }, 0);
692 |       });
693 |     }
694 |   });
695 | 
696 |   describe(`removeEventListener`, () => {
697 |     it(`remove added event listeners`, () => {
698 |       stubState('active');
699 | 
700 |       const lifecycle = new Lifecycle();
701 |       const listener = sinon.spy();
702 |       lifecycle.addEventListener('statechange', listener);
703 | 
704 |       simulateStateChange('active', 'passive');
705 | 
706 |       assert.equal(listener.callCount, 1);
707 |       assert(listener.getCall(0).calledWith(sinon.match({
708 |         type: 'statechange',
709 |         oldState: 'active',
710 |         newState: 'passive',
711 |         target: lifecycle,
712 |       })));
713 | 
714 |       // Remove the listener, then trigger a change to the 'passive' state.
715 |       lifecycle.removeEventListener('statechange', listener);
716 | 
717 |       simulateStateChange('passive', 'active');
718 | 
719 |       // Should not have been called again.
720 |       assert.equal(listener.callCount, 1);
721 |     });
722 |   });
723 | 
724 |   describe(`addUnsavedChanges`, () => {
725 |     it(`adds a beforeunload listener to warn about unsaved changes if one ` +
726 |         `isn't already added`, () => {
727 |       const lifecycle = new Lifecycle();
728 | 
729 |       const stub = sandbox.stub(self, 'addEventListener');
730 |       const id1 = {};
731 |       lifecycle.addUnsavedChanges(id1);
732 | 
733 |       assert(stub.calledOnce);
734 | 
735 |       const id2 = {};
736 |       lifecycle.addUnsavedChanges(id2);
737 | 
738 |       // It shouldn't have been called again.
739 |       assert(stub.calledOnce);
740 | 
741 |       const id3 = {};
742 |       lifecycle.addUnsavedChanges(id3);
743 | 
744 |       // It still shouldn't have been called again.
745 |       assert(stub.calledOnce);
746 |     });
747 |   });
748 | 
749 |   describe(`removeUnsavedChanges`, () => {
750 |     it(`removes a beforeunload listener to warn about unsaved changes if ` +
751 |         `no unsaved changes remain`, () => {
752 |       const lifecycle = new Lifecycle();
753 | 
754 |       const addEventListenerStub = sandbox.stub(self, 'addEventListener');
755 |       const removeEventListenerStub = sandbox.stub(self, 'removeEventListener');
756 | 
757 |       const id1 = {};
758 |       const id2 = {};
759 |       const id3 = {};
760 |       lifecycle.addUnsavedChanges(id1);
761 |       lifecycle.addUnsavedChanges(id2);
762 |       lifecycle.addUnsavedChanges(id3);
763 | 
764 |       assert(addEventListenerStub.calledOnce);
765 |       assert(removeEventListenerStub.notCalled);
766 | 
767 |       lifecycle.removeUnsavedChanges(id1);
768 |       lifecycle.removeUnsavedChanges(id2);
769 | 
770 |       assert(addEventListenerStub.calledOnce);
771 |       assert(removeEventListenerStub.notCalled);
772 | 
773 |       lifecycle.removeUnsavedChanges(id3);
774 | 
775 |       assert(addEventListenerStub.calledOnce);
776 |       assert(removeEventListenerStub.calledOnce);
777 |     });
778 |   });
779 | });
780 | 


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