├── .env ├── .gitignore ├── LICENSE ├── README.md ├── package-lock.json ├── package.json ├── public ├── favicon.ico ├── index.html └── manifest.json └── src ├── App.css ├── App.js ├── App.test.js ├── index.css ├── index.js ├── logo.svg └── serviceWorker.js /.env: -------------------------------------------------------------------------------- 1 | PUBLIC_URL=<%=PUBLIC_URL%> 2 | REACT_APP_ENV=<%-JSON.stringify(env)%> -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # See https://help.github.com/articles/ignoring-files/ for more about ignoring files. 2 | 3 | # dependencies 4 | /node_modules 5 | /.pnp 6 | .pnp.js 7 | 8 | # testing 9 | /coverage 10 | 11 | # production 12 | /build 13 | 14 | # misc 15 | .DS_Store 16 | .env.local 17 | .env.development.local 18 | .env.test.local 19 | .env.production.local 20 | 21 | npm-debug.log* 22 | yarn-debug.log* 23 | yarn-error.log* 24 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright 2018 Meltwater 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # react-immutable-example 2 | 3 | This project demonstrates how to convert to an [Immutable Web App](https://immutablwebapps.org) from a React app that was generated with [Create React App](https://github.com/facebook/create-react-app) version . 4 | 5 | ## Getting Started 6 | 7 | This project was created by running: 8 | 9 | ```bash 10 | > npx create-react-app react-immutable-example 11 | 12 | > cd react-immutable-example 13 | ``` 14 | 15 | ## Immutable Conversion 16 | 17 | Converting this this new application to build an Immutable Web App requires the following steps: 18 | 19 | 1. Referencing environment variables defined on `window` 20 | 2. Rendering an `index.html` template for deployments 21 | 3. Running locally 22 | 23 | ## Referencing environment variables defined on `window` 24 | 25 | Create React App has documentation for [adding custome environment variables](https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables). As they mention in the documentation, the environment variables are embedded during the build-time. To make the assets immutable, the setting of values must be shifted from build-time to run-time. Create React App has documentation for [injecting data from the server into the page](https://facebook.github.io/create-react-app/docs/title-and-meta-tags#injecting-data-from-the-server-into-the-page) which is similar to how this Immutable Web App example will handle environment variables. 26 | 27 | Change all references to point to the run-time browser `window` object instead of the build-time node `process` object: 28 | 29 | ```diff 30 | - process.env.REACT_APP_VARIABLE 31 | + window.env.REACT_APP_VARIABLE 32 | ``` 33 | 34 | ## Rendering an `index.html` template for deployments 35 | 36 | In theory, the role of `index.html` in an Immutable Web App is to be a deployment manifest that only contains configuration that is unique to the environment where it is deployed. 37 | 38 | In practice, there is often a need to include markup or scripts in the `index.html` that are more than just configuration, or that doesn't vary by environment, or that does change between versions of the app. This issue can be resolved by creating an _immutable_ `index.html` template, that is published with the other immutable assets. 39 | 40 | ### Converting index.html to a template 41 | 42 | This example uses [EJS](https://ejs.co/) as the templating language to render `index.html`, but any templating language can be used. 43 | 44 | 1) Identify the parts of the `index.html` that vary by environment: 45 | 46 | - [`PUBLIC_URL`](https://facebook.github.io/create-react-app/docs/using-the-public-folder#adding-assets-outside-of-the-module-system): URL where the versioned immutable assets will be deployed. 47 | - `window.env`: Environment-specific JavaScript configuration. 48 | 49 | 2) Set `PUBLIC_URL` to an EJS template string in the `.env`: 50 | 51 | ```diff 52 | + PUBLIC_URL=<%=PUBLIC_URL%> 53 | ``` 54 | 55 | 4) Set `REACT_APP_ENV` to an EJS template string in the `.env`. This will contain the JavaScript environment-specific variables.: 56 | 57 | ```diff 58 | PUBLIC_URL=<%=PUBLIC_URL%> 59 | + REACT_APP_ENV=<%-JSON.stringify(env)%> 60 | ``` 61 | 62 | 3) Add a new script tag to render the JavaScript environment-specific variables in `public/index.html`: 63 | 64 | ```diff 65 | 66 | ... 67 | + 70 | 71 | ``` 72 | 73 | ### Example 74 | 75 | #### `public/index.html`: 76 | 77 | __The source template that is converted into an immutable template during the build.__ 78 | 79 | ```html 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | React App 89 | 92 | 93 | 94 | 97 |
98 | 99 | 100 | ``` 101 | 102 | #### `.env` 103 | 104 | __The build-time environment variables used to generate the immutable template.__ 105 | 106 | ```sh 107 | PUBLIC_URL=<%=PUBLIC_URL%> 108 | REACT_APP_ENV=<%-JSON.stringify(env)%> 109 | ``` 110 | 111 | #### `dist/ng-immutable-example/index.ejs` 112 | 113 | __The immutable template that is published along with the other versioned, immutable assets.__ It is combined with `config.json` to render the `index.html` that is a deployment manifest. 114 | 115 | ```html 116 | 117 | 118 | 119 | 120 | 121 | 122 | 123 | 124 | React App 125 | 126 | 127 | 128 | 129 | 132 |
133 | 134 | 135 | 136 | 137 | 138 | ``` 139 | 140 | #### `config.json`: 141 | 142 | __The environments-specific values that vary.__ This is combined with the published immutable template to be rendered into `index.html`. It is not an immutable asset and should be managed as deployment-specific configuration. 143 | 144 | ```json 145 | { 146 | "PUBLIC_URL": "https://assets.react-immutable-example.com/1.0.0", 147 | "env": { 148 | "api": "https://api.react-immutable-example.com" 149 | } 150 | } 151 | ``` 152 | 153 | #### Rendered `index.html` 154 | 155 | __The environment-specific deployment manifest.__ It is the product of rendering an immutable template against the `config.json`. Publishing this file to the web application environment is an atomic deployment. 156 | 157 | ```html 158 | 159 | 160 | 161 | 162 | 163 | 164 | 165 | 166 | React App 167 | 168 | 169 | 170 | 171 | 174 |
175 | 176 | 177 | 178 | 179 | 180 | ``` 181 | 182 | ## Running Locally 183 | 184 | Without making any additional changes, `npm start` will run and serve the static assets as well as attempt to serve the immutable template `index.html`. A proper `index.html` can be rendered by [overriding the `.env`](https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables#what-other-env-files-can-be-used) file with values instead of template strings in an `.env.local` file. 185 | 186 | `.env`: 187 | 188 | ```sh 189 | PUBLIC_URL=<%=PUBLIC_URL%> 190 | REACT_APP_ENV=<%-JSON.stringify(env)%> 191 | ``` 192 | 193 | `.env.local`: 194 | 195 | ```sh 196 | PUBLIC_URL=/ 197 | REACT_APP_ENV={ api: "https://localhost:3001/api" } 198 | ``` 199 | 200 | ## Future Work 201 | 202 | This project will be updated as better patterns for building Immutable Web Apps are established and as [Create React App](https://github.com/facebook/create-react-app) changes. -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "react-immutable-example", 3 | "version": "0.1.0", 4 | "private": true, 5 | "dependencies": { 6 | "react": "^16.6.0", 7 | "react-dom": "^16.6.0", 8 | "react-scripts": "2.1.1" 9 | }, 10 | "scripts": { 11 | "start": "react-scripts start", 12 | "build": "react-scripts build", 13 | "test": "react-scripts test", 14 | "eject": "react-scripts eject" 15 | }, 16 | "eslintConfig": { 17 | "extends": "react-app" 18 | }, 19 | "browserslist": [ 20 | ">0.2%", 21 | "not dead", 22 | "not ie <= 11", 23 | "not op_mini all" 24 | ] 25 | } 26 | -------------------------------------------------------------------------------- /public/favicon.ico: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/ImmutableWebApps/react-immutable-example/9e119a88a73f63f0df774a1dc5312cccca58f1f6/public/favicon.ico -------------------------------------------------------------------------------- /public/index.html: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 12 | 13 | 22 | React App 23 | 26 | 27 | 28 | 31 |
32 | 42 | 43 | 44 | -------------------------------------------------------------------------------- /public/manifest.json: -------------------------------------------------------------------------------- 1 | { 2 | "short_name": "React App", 3 | "name": "Create React App Sample", 4 | "icons": [ 5 | { 6 | "src": "favicon.ico", 7 | "sizes": "64x64 32x32 24x24 16x16", 8 | "type": "image/x-icon" 9 | } 10 | ], 11 | "start_url": ".", 12 | "display": "standalone", 13 | "theme_color": "#000000", 14 | "background_color": "#ffffff" 15 | } 16 | -------------------------------------------------------------------------------- /src/App.css: -------------------------------------------------------------------------------- 1 | .App { 2 | text-align: center; 3 | } 4 | 5 | .App-logo { 6 | animation: App-logo-spin infinite 20s linear; 7 | height: 40vmin; 8 | } 9 | 10 | .App-header { 11 | background-color: #282c34; 12 | min-height: 100vh; 13 | display: flex; 14 | flex-direction: column; 15 | align-items: center; 16 | justify-content: center; 17 | font-size: calc(10px + 2vmin); 18 | color: white; 19 | } 20 | 21 | .App-link { 22 | color: #61dafb; 23 | } 24 | 25 | @keyframes App-logo-spin { 26 | from { 27 | transform: rotate(0deg); 28 | } 29 | to { 30 | transform: rotate(360deg); 31 | } 32 | } 33 | -------------------------------------------------------------------------------- /src/App.js: -------------------------------------------------------------------------------- 1 | import React, { Component } from 'react'; 2 | import logo from './logo.svg'; 3 | import './App.css'; 4 | 5 | class App extends Component { 6 | render() { 7 | return ( 8 |
9 |
10 | logo 11 |

12 | Edit src/App.js and save to reload. 13 |

14 | 20 | Learn React 21 | 22 |
23 |
24 | ); 25 | } 26 | } 27 | 28 | export default App; 29 | -------------------------------------------------------------------------------- /src/App.test.js: -------------------------------------------------------------------------------- 1 | import React from 'react'; 2 | import ReactDOM from 'react-dom'; 3 | import App from './App'; 4 | 5 | it('renders without crashing', () => { 6 | const div = document.createElement('div'); 7 | ReactDOM.render(, div); 8 | ReactDOM.unmountComponentAtNode(div); 9 | }); 10 | -------------------------------------------------------------------------------- /src/index.css: -------------------------------------------------------------------------------- 1 | body { 2 | margin: 0; 3 | padding: 0; 4 | font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", 5 | "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", 6 | sans-serif; 7 | -webkit-font-smoothing: antialiased; 8 | -moz-osx-font-smoothing: grayscale; 9 | } 10 | 11 | code { 12 | font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New", 13 | monospace; 14 | } 15 | -------------------------------------------------------------------------------- /src/index.js: -------------------------------------------------------------------------------- 1 | import React from 'react'; 2 | import ReactDOM from 'react-dom'; 3 | import './index.css'; 4 | import App from './App'; 5 | import * as serviceWorker from './serviceWorker'; 6 | 7 | ReactDOM.render(, document.getElementById('root')); 8 | 9 | // If you want your app to work offline and load faster, you can change 10 | // unregister() to register() below. Note this comes with some pitfalls. 11 | // Learn more about service workers: http://bit.ly/CRA-PWA 12 | serviceWorker.unregister(); 13 | -------------------------------------------------------------------------------- /src/logo.svg: -------------------------------------------------------------------------------- 1 | -------------------------------------------------------------------------------- /src/serviceWorker.js: -------------------------------------------------------------------------------- 1 | // This optional code is used to register a service worker. 2 | // register() is not called by default. 3 | 4 | // This lets the app load faster on subsequent visits in production, and gives 5 | // it offline capabilities. However, it also means that developers (and users) 6 | // will only see deployed updates on subsequent visits to a page, after all the 7 | // existing tabs open on the page have been closed, since previously cached 8 | // resources are updated in the background. 9 | 10 | // To learn more about the benefits of this model and instructions on how to 11 | // opt-in, read http://bit.ly/CRA-PWA 12 | 13 | const isLocalhost = Boolean( 14 | window.location.hostname === 'localhost' || 15 | // [::1] is the IPv6 localhost address. 16 | window.location.hostname === '[::1]' || 17 | // 127.0.0.1/8 is considered localhost for IPv4. 18 | window.location.hostname.match( 19 | /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/ 20 | ) 21 | ); 22 | 23 | export function register(config) { 24 | if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) { 25 | // The URL constructor is available in all browsers that support SW. 26 | const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href); 27 | if (publicUrl.origin !== window.location.origin) { 28 | // Our service worker won't work if PUBLIC_URL is on a different origin 29 | // from what our page is served on. This might happen if a CDN is used to 30 | // serve assets; see https://github.com/facebook/create-react-app/issues/2374 31 | return; 32 | } 33 | 34 | window.addEventListener('load', () => { 35 | const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`; 36 | 37 | if (isLocalhost) { 38 | // This is running on localhost. Let's check if a service worker still exists or not. 39 | checkValidServiceWorker(swUrl, config); 40 | 41 | // Add some additional logging to localhost, pointing developers to the 42 | // service worker/PWA documentation. 43 | navigator.serviceWorker.ready.then(() => { 44 | console.log( 45 | 'This web app is being served cache-first by a service ' + 46 | 'worker. To learn more, visit http://bit.ly/CRA-PWA' 47 | ); 48 | }); 49 | } else { 50 | // Is not localhost. Just register service worker 51 | registerValidSW(swUrl, config); 52 | } 53 | }); 54 | } 55 | } 56 | 57 | function registerValidSW(swUrl, config) { 58 | navigator.serviceWorker 59 | .register(swUrl) 60 | .then(registration => { 61 | registration.onupdatefound = () => { 62 | const installingWorker = registration.installing; 63 | if (installingWorker == null) { 64 | return; 65 | } 66 | installingWorker.onstatechange = () => { 67 | if (installingWorker.state === 'installed') { 68 | if (navigator.serviceWorker.controller) { 69 | // At this point, the updated precached content has been fetched, 70 | // but the previous service worker will still serve the older 71 | // content until all client tabs are closed. 72 | console.log( 73 | 'New content is available and will be used when all ' + 74 | 'tabs for this page are closed. See http://bit.ly/CRA-PWA.' 75 | ); 76 | 77 | // Execute callback 78 | if (config && config.onUpdate) { 79 | config.onUpdate(registration); 80 | } 81 | } else { 82 | // At this point, everything has been precached. 83 | // It's the perfect time to display a 84 | // "Content is cached for offline use." message. 85 | console.log('Content is cached for offline use.'); 86 | 87 | // Execute callback 88 | if (config && config.onSuccess) { 89 | config.onSuccess(registration); 90 | } 91 | } 92 | } 93 | }; 94 | }; 95 | }) 96 | .catch(error => { 97 | console.error('Error during service worker registration:', error); 98 | }); 99 | } 100 | 101 | function checkValidServiceWorker(swUrl, config) { 102 | // Check if the service worker can be found. If it can't reload the page. 103 | fetch(swUrl) 104 | .then(response => { 105 | // Ensure service worker exists, and that we really are getting a JS file. 106 | const contentType = response.headers.get('content-type'); 107 | if ( 108 | response.status === 404 || 109 | (contentType != null && contentType.indexOf('javascript') === -1) 110 | ) { 111 | // No service worker found. Probably a different app. Reload the page. 112 | navigator.serviceWorker.ready.then(registration => { 113 | registration.unregister().then(() => { 114 | window.location.reload(); 115 | }); 116 | }); 117 | } else { 118 | // Service worker found. Proceed as normal. 119 | registerValidSW(swUrl, config); 120 | } 121 | }) 122 | .catch(() => { 123 | console.log( 124 | 'No internet connection found. App is running in offline mode.' 125 | ); 126 | }); 127 | } 128 | 129 | export function unregister() { 130 | if ('serviceWorker' in navigator) { 131 | navigator.serviceWorker.ready.then(registration => { 132 | registration.unregister(); 133 | }); 134 | } 135 | } 136 | --------------------------------------------------------------------------------