├── .eslintrc.json
├── .gitignore
├── LICENSE
├── README.md
├── jest.config.js
├── package.json
├── rollup.config.js
├── src
    ├── __tests__
    │   └── react-hooks.ts
    └── react-hooks.ts
├── stories
    ├── addons.js
    ├── config.js
    ├── react-hooks.stories.js
    └── webpack.config.js
├── tsconfig.json
└── yarn.lock


/.eslintrc.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "env": {
 3 |     "browser": true,
 4 |     "commonjs": true,
 5 |     "es6": true,
 6 |     "node": true
 7 |   },
 8 |   "parser": "@typescript-eslint/parser",
 9 |   "parserOptions": {
10 |     "sourceType": "module",
11 |     "ecmaFeatures": {
12 |       "jsx": true
13 |     }
14 |   },
15 |   "plugins": [
16 |     "@typescript-eslint",
17 |     "jest",
18 | 		"react",
19 | 		"react-hooks",
20 |     "prettier"
21 |   ],
22 |   "extends": [
23 |     "eslint:recommended",
24 |     "plugin:@typescript-eslint/recommended",
25 |     "plugin:jest/recommended",
26 |     "plugin:prettier/recommended",
27 |     "prettier/@typescript-eslint"
28 |   ],
29 |   "rules": {
30 |     "prettier/prettier": [
31 |       "error",
32 |       {
33 |         "trailingComma": "all",
34 |         "arrowParens": "always"
35 |       }
36 |     ],
37 |     "linebreak-style": ["error", "unix"],
38 |     "@typescript-eslint/explicit-function-return-type": 0,
39 |     "@typescript-eslint/explicit-member-accessibility": 0,
40 |     "@typescript-eslint/no-explicit-any": 0,
41 |     "@typescript-eslint/no-object-literal-type-assertion": 0,
42 |     "@typescript-eslint/no-non-null-assertion": 0,
43 |     "@typescript-eslint/no-parameter-properties": 0,
44 |     "@typescript-eslint/no-unused-vars": [
45 |       "error",
46 |       {
47 |         "argsIgnorePattern": "^_",
48 |         "varsIgnorePattern": "^_"
49 |       }
50 |     ],
51 | 		"react/prop-types": 0,
52 | 		"react-hooks/rules-of-hooks": "error",
53 | 		"react-hooks/exhaustive-deps": "warn"
54 |   }
55 | }
56 | 


--------------------------------------------------------------------------------
/.gitignore:
--------------------------------------------------------------------------------
1 | node_modules
2 | lib
3 | coverage
4 | .rpt2_cache
5 | npm-debug.log*
6 | yarn-debug.log*
7 | yarn-error.log*
8 | lerna-debug.log*
9 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
1 | Copyright 2019 Brian Kim
2 | 
3 | Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
4 | 
5 | The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
6 | 
7 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
8 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
  1 | # @repeaterjs/react-hooks
  2 | React hooks for working with async iterators/generators.
  3 | 
  4 | These functions are implemented with repeaters. For more information about repeaters, visit [repeater.js.org](https://repeater.js.org).
  5 | 
  6 | ## Installation
  7 | ```
  8 | npm install @repeaterjs/react-hooks
  9 | ```
 10 | 
 11 | ```
 12 | yarn add @repeaterjs/react-hooks
 13 | ```
 14 | 
 15 | ## API
 16 | ### `useResult`
 17 | ```ts
 18 | declare function useResult<T, TDeps extends any[]>(
 19 |   callback: (deps: AsyncIterableIterator<TDeps>) => AsyncIterableIterator<T>,
 20 |   deps?: TDeps,
 21 | ): IteratorResult<T> | undefined;
 22 | 
 23 | import {useResult} from "@repeaterjs/react-hooks";
 24 | 
 25 | const result = useResult(async function *() {
 26 |   /* ... */
 27 | });
 28 | ```
 29 | 
 30 | `callback` is a function which returns an async iterator, usually an async generator function. The callback is called when the component initializes and the returned iterator updates the component whenever it produces results. `useResult` returns an `IteratorResult`, an object of type `{value: T, done: boolean}`, where `T` is the type of the produced values, and `done` indicates whether the iterator has returned. The first return value from this hook will be `undefined`, indicating that the iterator has yet to produce any values.
 31 | 
 32 | ```ts
 33 | function Timer() {
 34 |   const result = useResult(async function*() {
 35 |     let i = 0;
 36 |     while (true) {
 37 |       yield i++
 38 |       await new Promise((resolve) => setTimeout(resolve, 1000));
 39 |     }
 40 |   });
 41 | 
 42 |   return <div>Seconds: {result && result.value}</div>;
 43 | }
 44 | ```
 45 | 
 46 | Similar to the `useEffect` hook, `useResult` accepts an array of dependencies as a second argument. However, rather than being referenced via closure, the dependencies are passed into the callback as an async iterator which updates whenever any of the dependencies change. We pass the dependencies in manually because `callback` is only called once, and dependencies referenced via closure become stale as the component updates.
 47 | 
 48 | ```ts
 49 | function ProductDetail({productId}) {
 50 |   const result = useResult(async function *(deps) {
 51 |     for await (const [productId] of deps) {
 52 |       const data = await fetchProductData(productId);
 53 |       yield data.description;
 54 |     }
 55 |   }, [productId]);
 56 | 
 57 |   if (result == null) {
 58 |     return <div>Loading...</div>;
 59 |   }
 60 | 
 61 |   return <div>Description: {result.value}</div>;
 62 | }
 63 | ```
 64 | 
 65 | ### `useValue`
 66 | ```ts
 67 | declare function useValue<T, TDeps extends any[]>(
 68 |   callback: (deps: AsyncIterableIterator<TDeps>) => AsyncIterableIterator<T>,
 69 |   deps?: TDeps,
 70 | ): T | undefined;
 71 | 
 72 | import {useValue} from "@repeaterjs/react-hooks";
 73 | 
 74 | const value = useValue(async function *() {
 75 |   /* ... */
 76 | });
 77 | ```
 78 | 
 79 | Similar to `useResult`, except the `IteratorResult`’s value is returned rather than the `IteratorResult` object itself. Prefer `useValue` over `useResult` when you don’t need to distinguish between whether values were yielded or returned.
 80 | 
 81 | ### `useAsyncIter`
 82 | ```ts
 83 | declare function useAsyncIter<T, TDeps extends any[]>(
 84 |   callback: (deps: AsyncIterableIterator<TDeps>) => AsyncIterableIterator<T>,
 85 |   deps: TDeps = ([] as unknown) as TDeps,
 86 | ): AsyncIterableIterator<T>;
 87 | 
 88 | import {useAsyncIter} from "@repeaterjs/react-hooks";
 89 | 
 90 | function MyComponent() {
 91 |   const iter = useAsyncIter(async function *() {
 92 |     /* ... */
 93 |   });
 94 |   /* ... */
 95 | }
 96 | ```
 97 | 
 98 | Similar to `useResult` and `useValue`, except that `useAsyncIter` returns the async iterator itself rather than consuming it. The returned async iterator can be referenced via closure in further `useResult` calls. Prefer `useAsyncIter` over `useResult` or `useValue` when you want to use an async iterator without updating each time a value is produced.
 99 | 
100 | ```ts
101 | const konami = ["ArrowUp", "ArrowUp", "ArrowDown", "ArrowDown", "ArrowLeft", "ArrowRight", "ArrowLeft", "ArrowRight", "b", "a"];
102 | function Cheats() {
103 |   const keys = useAsyncIter(() => {
104 |     return new Repeater(async (push, stop) => {
105 |       const listener = (ev) => push(ev.key);
106 |       window.addEventListener("keyup", listener);
107 |       await stop;
108 |       window.removeEventListener("keyup", listener);
109 |     });
110 |   });
111 | 
112 |   const result = useResult(async function *() {
113 |     let i = 0;
114 |     yield konami[i];
115 |     for await (const key of keys) {
116 |       if (key === konami[i]) {
117 |         i++;
118 |       } else {
119 |         i = 0;
120 |       }
121 | 
122 |       if (i < konami.length) {
123 |         yield konami[i];
124 |       } else {
125 |         return "Cheats activated";
126 |       }
127 |     }
128 |   });
129 | 
130 |   if (result == null) {
131 |     return null;
132 |   } else if (result.done) {
133 |     return <div>🎉 {result.value} 🎉</div>;
134 |   }
135 | 
136 |   return <div>Next key: {result.value}</div>;
137 | }
138 | ```
139 | 
140 | ### `useRepeater`
141 | ```ts
142 | declare function useRepeater<T>(
143 |   buffer?: RepeaterBuffer<T>,
144 | ): [Repeater<T>, Push<T>, Stop];
145 | 
146 | import { useRepeater } from "@repeaterjs/react-hooks";
147 | import { SlidingBuffer } from "@repeaterjs/repeater";
148 | 
149 | function MyComponent() {
150 |   const [repeater, push, stop] = useRepeater(new SlidingBuffer(10));
151 |   /* ... */
152 | }
153 | ```
154 | 
155 | Creates a repeater which can be used in useResult callbacks. `push` and `stop`
156 | can be used in later callbacks to update the repeater. For more information about
157 | the `push` and `stop` functions or the `buffer` argument, refer to the
158 | [repeater.js docs](https://repeater.js.org/docs/overview).
159 | 
160 | ```ts
161 | function MarkdownEditor() {
162 |   const [inputs, push] = useRepeater();
163 |   const result = useResult(async function*() {
164 |     const md = new Remarkable();
165 |     for await (const input of inputs) {
166 |       yield md.render(input);
167 |     }
168 |   });
169 |   return (
170 |     <div>
171 |       <h3>Input</h3>
172 |       <textarea
173 |         defaultValue="Hello, **world**!"
174 |         onChange={(ev) => push(ev.target.value)}
175 |       />
176 |       <h3>Output</h3>
177 |       <div dangerouslySetInnnerHTML={{ __html: result && result.value }} />
178 |     </div>
179 |   );
180 | }
181 | ```
182 | 
183 | See also:
184 | - [react-coroutine](https://github.com/alexeyraspopov/react-coroutine) Define React components with generators, async functions and async generators.
185 | 


--------------------------------------------------------------------------------
/jest.config.js:
--------------------------------------------------------------------------------
  1 | // For a detailed explanation regarding each configuration property, visit:
  2 | // https://jestjs.io/docs/en/configuration.html
  3 | 
  4 | module.exports = {
  5 |   // All imported modules in your tests should be mocked automatically
  6 |   // automock: false,
  7 | 
  8 |   // Stop running tests after `n` failures
  9 |   // bail: 0,
 10 | 
 11 |   // Respect "browser" field in package.json when resolving modules
 12 |   // browser: false,
 13 | 
 14 |   // The directory where Jest should store its cached dependency information
 15 |   // cacheDirectory: "/private/var/folders/5t/bqn5fb4s0bs4qdbjv9zdn28r0000gn/T/jest_dx",
 16 | 
 17 |   // Automatically clear mock calls and instances between every test
 18 |   clearMocks: true,
 19 | 
 20 |   // Indicates whether the coverage information should be collected while executing the test
 21 |   // collectCoverage: false,
 22 | 
 23 |   // An array of glob patterns indicating a set of files for which coverage information should be collected
 24 |   // collectCoverageFrom: null,
 25 | 
 26 |   // The directory where Jest should output its coverage files
 27 |   // coverageDirectory: "coverage",
 28 | 
 29 |   // An array of regexp pattern strings used to skip coverage collection
 30 |   // coveragePathIgnorePatterns: [
 31 |   //   "/node_modules/"
 32 |   // ],
 33 | 
 34 |   // A list of reporter names that Jest uses when writing coverage reports
 35 |   // coverageReporters: [
 36 |   //   "json",
 37 |   //   "text",
 38 |   //   "lcov",
 39 |   //   "clover"
 40 |   // ],
 41 | 
 42 |   // An object that configures minimum threshold enforcement for coverage results
 43 |   // coverageThreshold: null,
 44 | 
 45 |   // A path to a custom dependency extractor
 46 |   // dependencyExtractor: null,
 47 | 
 48 |   // Make calling deprecated APIs throw helpful error messages
 49 |   // errorOnDeprecated: false,
 50 | 
 51 |   // Force coverage collection from ignored files using an array of glob patterns
 52 |   // forceCoverageMatch: [],
 53 | 
 54 |   // A path to a module which exports an async function that is triggered once before all test suites
 55 |   // globalSetup: null,
 56 | 
 57 |   // A path to a module which exports an async function that is triggered once after all test suites
 58 |   // globalTeardown: null,
 59 | 
 60 |   // A set of global variables that need to be available in all test environments
 61 |   globals: {
 62 |     "ts-jest": {
 63 |       tsConfig: {
 64 |         target: "esnext",
 65 |       },
 66 |       diagnostics: {
 67 |         ignoreCodes: [151001],
 68 |       },
 69 |     },
 70 |   },
 71 | 
 72 |   // An array of directory names to be searched recursively up from the requiring module's location
 73 |   // moduleDirectories: [
 74 |   //   "node_modules"
 75 |   // ],
 76 | 
 77 |   // An array of file extensions your modules use
 78 |   moduleFileExtensions: ["js", "json", "jsx", "ts", "tsx", "node"],
 79 | 
 80 |   // A map from regular expressions to module names that allow to stub out resources with a single module
 81 |   // moduleNameMapper: {},
 82 | 
 83 |   // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
 84 |   // modulePathIgnorePatterns: [],
 85 | 
 86 |   // Activates notifications for test results
 87 |   // notify: false,
 88 | 
 89 |   // An enum that specifies notification mode. Requires { notify: true }
 90 |   // notifyMode: "failure-change",
 91 | 
 92 |   // A preset that is used as a base for Jest's configuration
 93 |   // preset: null,
 94 | 
 95 |   // Run tests from one or more projects
 96 |   // projects: null,
 97 | 
 98 |   // Use this configuration option to add custom reporters to Jest
 99 |   // reporters: undefined,
100 | 
101 |   // Automatically reset mock state between every test
102 |   // resetMocks: false,
103 | 
104 |   // Reset the module registry before running each individual test
105 |   // resetModules: false,
106 | 
107 |   // A path to a custom resolver
108 |   // resolver: null,
109 | 
110 |   // Automatically restore mock state between every test
111 |   // restoreMocks: false,
112 | 
113 |   // The root directory that Jest should scan for tests and modules within
114 |   // rootDir: null,
115 | 
116 |   // A list of paths to directories that Jest should use to search for files in
117 |   // roots: [
118 |   //   "<rootDir>"
119 |   // ],
120 | 
121 |   // Allows you to use a custom runner instead of Jest's default test runner
122 |   // runner: "jest-runner",
123 | 
124 |   // The paths to modules that run some code to configure or set up the testing environment before each test
125 |   // setupFiles: [],
126 | 
127 |   // A list of paths to modules that run some code to configure or set up the testing framework before each test
128 |   // setupFilesAfterEnv: [],
129 | 
130 |   // A list of paths to snapshot serializer modules Jest should use for snapshot testing
131 |   // snapshotSerializers: [],
132 | 
133 |   // The test environment that will be used for testing
134 |   // testEnvironment: "jest-environment-jsdom",
135 | 
136 |   // Options that will be passed to the testEnvironment
137 |   // testEnvironmentOptions: {},
138 | 
139 |   // Adds a location field to test results
140 |   // testLocationInResults: false,
141 | 
142 |   // The glob patterns Jest uses to detect test files
143 |   // testMatch: [
144 |   //   "**/__tests__/**/*.[jt]s?(x)",
145 |   //   "**/?(*.)+(spec|test).[tj]s?(x)"
146 |   // ],
147 | 
148 |   // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
149 |   // testPathIgnorePatterns: [
150 |   //   "/node_modules/"
151 |   // ],
152 | 
153 |   // The regexp pattern or array of patterns that Jest uses to detect test files
154 |   // testRegex: [],
155 | 
156 |   // This option allows the use of a custom results processor
157 |   // testResultsProcessor: null,
158 | 
159 |   // This option allows use of a custom test runner
160 |   // testRunner: "jasmine2",
161 | 
162 |   // This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
163 |   // testURL: "http://localhost",
164 | 
165 |   // Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
166 |   // timers: "real",
167 | 
168 |   // A map from regular expressions to paths to transformers
169 |   transform: {
170 |     "^.+\\.tsx?$": "ts-jest",
171 |   },
172 | 
173 |   // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
174 |   // transformIgnorePatterns: [
175 |   //   "/node_modules/"
176 |   // ],
177 | 
178 |   // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
179 |   // unmockedModulePathPatterns: undefined,
180 | 
181 |   // Indicates whether each individual test should be reported during the run
182 |   // verbose: true,
183 | 
184 |   // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
185 |   // watchPathIgnorePatterns: [],
186 | 
187 |   // Whether to use watchman for file crawling
188 |   // watchman: true,
189 | };
190 | 


--------------------------------------------------------------------------------
/package.json:
--------------------------------------------------------------------------------
 1 | {
 2 |   "name": "@repeaterjs/react-hooks",
 3 |   "version": "0.1.1",
 4 |   "description": "React hooks for using async iterators in components",
 5 |   "repository": {
 6 |     "type": "git",
 7 |     "url": "https://github.com/repeaterjs/repeater",
 8 |     "directory": "packages/repeater"
 9 |   },
10 |   "license": "MIT",
11 |   "files": [
12 |     "/lib"
13 |   ],
14 |   "main": "lib/react-hooks.cjs.js",
15 |   "module": "lib/react-hooks.esm.js",
16 |   "types": "lib/react-hooks.d.ts",
17 |   "scripts": {
18 |     "prebuild": "yarn run clean",
19 |     "build": "rollup -c rollup.config.js",
20 |     "clean": "shx rm -rf ./lib",
21 |     "lint": "eslint --ignore-path .gitignore --ext .js,.ts,.tsx .",
22 |     "prepublishOnly": "yarn run test && yarn run build",
23 |     "test": "jest --config jest.config.js --color",
24 |     "start-storybook": "start-storybook -p 1337 --config-dir stories",
25 |     "build-storybook": "build-storybook --config-dir stories"
26 |   },
27 |   "dependencies": {
28 |     "@repeaterjs/repeater": "^3.0.1"
29 |   },
30 |   "devDependencies": {
31 |     "@babel/core": "^7.7.2",
32 |     "@storybook/addon-actions": "^5.2.6",
33 |     "@storybook/addon-links": "^5.2.6",
34 |     "@storybook/addon-storysource": "^5.2.6",
35 |     "@storybook/addons": "^5.2.6",
36 |     "@storybook/react": "^5.2.6",
37 |     "@testing-library/react-hooks": "^3.2.1",
38 |     "@types/jest": "^24.0.22",
39 |     "@types/react": "^16.9.11",
40 |     "@typescript-eslint/eslint-plugin": "^2.6.1",
41 |     "@typescript-eslint/parser": "^2.6.1",
42 |     "babel-loader": "^8.0.6",
43 |     "eslint": "^6.6.0",
44 |     "eslint-config-prettier": "^6.5.0",
45 |     "eslint-plugin-jest": "^23.0.3",
46 |     "eslint-plugin-prettier": "^3.1.1",
47 |     "eslint-plugin-react": "^7.16.0",
48 |     "eslint-plugin-react-hooks": "^2.2.0",
49 |     "jest": "^24.9.0",
50 |     "prettier": "^1.19.1",
51 |     "react": "^16.11.0",
52 |     "react-test-renderer": "^16.11.0",
53 |     "rollup": "^1.26.4",
54 |     "rollup-plugin-typescript2": "^0.25.2",
55 |     "shx": "^0.3.2",
56 |     "ts-jest": "^24.1.0",
57 |     "typescript": "^3.7.2",
58 |     "weak": "^1.0.1"
59 |   },
60 |   "peerDependencies": {
61 |     "react": "^16.8.0"
62 |   },
63 |   "publishConfig": {
64 |     "access": "public"
65 |   }
66 | }
67 | 


--------------------------------------------------------------------------------
/rollup.config.js:
--------------------------------------------------------------------------------
 1 | import path from "path";
 2 | import typescript from "rollup-plugin-typescript2";
 3 | 
 4 | const root = process.cwd();
 5 | const pkg = require(path.join(root, "package.json")); // eslint-disable-line
 6 | 
 7 | export default {
 8 |   input: path.join(root, "src/react-hooks.ts"),
 9 |   output: [
10 |     {
11 |       file: pkg.main,
12 |       format: "cjs",
13 |       sourcemap: true,
14 |     },
15 |     {
16 |       file: pkg.module,
17 |       format: "esm",
18 |       sourcemap: true,
19 |     },
20 |   ],
21 |   plugins: [typescript()],
22 |   external: ["react", "@repeaterjs/repeater"],
23 | };
24 | 


--------------------------------------------------------------------------------
/src/__tests__/react-hooks.ts:
--------------------------------------------------------------------------------
  1 | import { act } from "react-test-renderer";
  2 | import { Push, Repeater, Stop } from "@repeaterjs/repeater";
  3 | import { renderHook } from "@testing-library/react-hooks";
  4 | import { useAsyncIter, useRepeater, useResult, useValue } from "../react-hooks";
  5 | 
  6 | describe("useRepeater", () => {
  7 |   test("basic", async () => {
  8 |     const { result } = renderHook(() => {
  9 |       return useRepeater();
 10 |     });
 11 | 
 12 |     const [repeater, push, stop] = result.current;
 13 |     expect(repeater).toBeDefined();
 14 |     expect(push).toBeDefined();
 15 |     expect(stop).toBeDefined();
 16 |     push(1);
 17 |     expect(await repeater.next()).toEqual({ value: 1, done: false });
 18 |     push(2);
 19 |     expect(await repeater.next()).toEqual({ value: 2, done: false });
 20 |     push(3);
 21 |     push(4);
 22 |     expect(await repeater.next()).toEqual({ value: 3, done: false });
 23 |     expect(await repeater.next()).toEqual({ value: 4, done: false });
 24 |     stop();
 25 |     expect(await repeater.next()).toEqual({ done: true });
 26 |   });
 27 | });
 28 | 
 29 | describe("useAsyncIter", () => {
 30 |   test("basic", async () => {
 31 |     const callback = jest.fn(async function*(): AsyncIterableIterator<number> {
 32 |       yield 1;
 33 |       await new Promise((resolve) => setTimeout(resolve, 100));
 34 |       yield 2;
 35 |       await new Promise((resolve) => setTimeout(resolve, 100));
 36 |       yield 3;
 37 |       await new Promise((resolve) => setTimeout(resolve, 100));
 38 |       yield 4;
 39 |     });
 40 | 
 41 |     const { result, rerender } = renderHook(() => {
 42 |       return useAsyncIter(callback);
 43 |     });
 44 | 
 45 |     expect(await result.current.next()).toEqual({ value: 1, done: false });
 46 |     rerender();
 47 |     expect(await result.current.next()).toEqual({ value: 2, done: false });
 48 |     rerender();
 49 |     expect(await result.current.next()).toEqual({ value: 3, done: false });
 50 |   });
 51 | 
 52 |   test("unmount", async () => {
 53 |     const callback = jest.fn(async function*(): AsyncIterableIterator<number> {
 54 |       yield 1;
 55 |       await new Promise((resolve) => setTimeout(resolve, 100));
 56 |       yield 2;
 57 |       await new Promise((resolve) => setTimeout(resolve, 100));
 58 |       yield 3;
 59 |       await new Promise((resolve) => setTimeout(resolve, 100));
 60 |       yield 4;
 61 |     });
 62 | 
 63 |     const { result, unmount } = renderHook(() => {
 64 |       return useAsyncIter(callback);
 65 |     });
 66 | 
 67 |     expect(await result.current.next()).toEqual({ value: 1, done: false });
 68 |     unmount();
 69 |     expect(await result.current.next()).toEqual({ done: true });
 70 |     expect(callback).toHaveBeenCalledTimes(1);
 71 |   });
 72 | 
 73 |   test("deps", async () => {
 74 |     const callback = jest.fn(async function*(
 75 |       deps: AsyncIterableIterator<[number]>,
 76 |     ): AsyncIterableIterator<number> {
 77 |       for await (const [num] of deps) {
 78 |         yield num ** 2;
 79 |       }
 80 |     });
 81 | 
 82 |     const { result, rerender } = renderHook(
 83 |       (props) => {
 84 |         return useAsyncIter(callback, [props.num]);
 85 |       },
 86 |       { initialProps: { num: 1 } },
 87 |     );
 88 | 
 89 |     expect(await result.current.next()).toEqual({ value: 1, done: false });
 90 |     rerender({ num: 2 });
 91 |     expect(await result.current.next()).toEqual({ value: 4, done: false });
 92 |     rerender({ num: 3 });
 93 |     rerender({ num: 4 });
 94 |     expect(await result.current.next()).toEqual({ value: 9, done: false });
 95 |     expect(await result.current.next()).toEqual({ value: 16, done: false });
 96 |   });
 97 | });
 98 | 
 99 | describe("useResult", () => {
100 |   test("basic", async () => {
101 |     let push: Push<number>;
102 |     let stop: Stop;
103 |     const repeater = new Repeater(async (push1, stop1) => {
104 |       push = push1;
105 |       stop = stop1;
106 |       return -1;
107 |     });
108 | 
109 |     const callback = jest.fn(() => {
110 |       return repeater;
111 |     });
112 | 
113 |     const { result } = renderHook(() => {
114 |       return useResult(callback);
115 |     });
116 | 
117 |     expect(result.current).toBeUndefined();
118 |     await act(async () => void (await push(1)));
119 |     expect(result.current).toEqual({ value: 1, done: false });
120 |     await act(async () => void (await push(2)));
121 |     expect(result.current).toEqual({ value: 2, done: false });
122 |     await act(async () => void (await push(3)));
123 |     expect(result.current).toEqual({ value: 3, done: false });
124 |     await act(async () => void (await push(4)));
125 |     expect(result.current).toEqual({ value: 4, done: false });
126 |     await act(async () => (stop(), stop));
127 |     expect(result.current).toEqual({ value: -1, done: true });
128 |     expect(callback).toHaveBeenCalledTimes(1);
129 |   });
130 | 
131 |   test("unmount", async () => {
132 |     let push: Push<number>;
133 |     const repeater = new Repeater(async (push1) => {
134 |       push = push1;
135 |       return -1;
136 |     });
137 | 
138 |     const callback = jest.fn(() => {
139 |       return repeater;
140 |     });
141 |     const returnSpy = jest.spyOn(repeater, "return");
142 |     const { result, unmount } = renderHook(() => {
143 |       return useResult(callback);
144 |     });
145 | 
146 |     expect(result.current).toBeUndefined();
147 |     await act(async () => void (await push(1)));
148 |     expect(result.current).toEqual({ value: 1, done: false });
149 |     unmount();
150 |     expect(callback).toHaveBeenCalledTimes(1);
151 |     expect(returnSpy).toHaveBeenCalledTimes(1);
152 |   });
153 | 
154 |   test("deps", async () => {
155 |     const callback = jest.fn((deps) => {
156 |       return new Repeater<number>(async (push) => {
157 |         for await (const [num] of deps) {
158 |           await push(num);
159 |         }
160 | 
161 |         return -1;
162 |       });
163 |     });
164 | 
165 |     const { result, rerender, waitForNextUpdate } = renderHook(
166 |       (props) => {
167 |         return useResult(callback, [props.num]);
168 |       },
169 |       { initialProps: { num: 1 } },
170 |     );
171 | 
172 |     expect(result.current).toBeUndefined();
173 |     await waitForNextUpdate();
174 |     expect(result.current).toEqual({ value: 1, done: false });
175 |     rerender({ num: 2 });
176 |     expect(result.current).toEqual({ value: 1, done: false });
177 |     await waitForNextUpdate();
178 |     expect(result.current).toEqual({ value: 2, done: false });
179 |     rerender({ num: 3 });
180 |     expect(result.current).toEqual({ value: 2, done: false });
181 |     await waitForNextUpdate();
182 |     expect(result.current).toEqual({ value: 3, done: false });
183 |     expect(callback).toHaveBeenCalledTimes(1);
184 |   });
185 | });
186 | 
187 | describe("useValue", () => {
188 |   test("basic", async () => {
189 |     let push: Push<number>;
190 |     let stop: Stop;
191 |     const repeater = new Repeater(async (push1, stop1) => {
192 |       push = push1;
193 |       stop = stop1;
194 |       return -1;
195 |     });
196 | 
197 |     const callback = jest.fn(() => {
198 |       return repeater;
199 |     });
200 | 
201 |     const { result, rerender } = renderHook(() => {
202 |       return useValue(callback);
203 |     });
204 | 
205 |     expect(result.current).toBeUndefined();
206 |     await act(async () => void (await push(1)));
207 |     expect(result.current).toBe(1);
208 |     await act(async () => void (await push(2)));
209 |     expect(result.current).toBe(2);
210 |     await act(async () => void (await push(3)));
211 |     expect(result.current).toBe(3);
212 |     await act(async () => void (await push(4)));
213 |     expect(result.current).toBe(4);
214 |     await act(async () => (stop(), stop));
215 |     expect(result.current).toBe(-1);
216 |     rerender();
217 |     expect(result.current).toBe(-1);
218 |     expect(callback).toHaveBeenCalledTimes(1);
219 |   });
220 | 
221 |   test("unmount", async () => {
222 |     let push: Push<number>;
223 |     const repeater = new Repeater(async (push1) => {
224 |       push = push1;
225 |       return -1;
226 |     });
227 | 
228 |     const callback = jest.fn(() => {
229 |       return repeater;
230 |     });
231 | 
232 |     const returnSpy = jest.spyOn(repeater, "return");
233 |     const { result, unmount } = renderHook(() => {
234 |       return useValue(callback);
235 |     });
236 | 
237 |     expect(result.current).toBeUndefined();
238 |     await act(async () => void (await push(1)));
239 |     expect(result.current).toBe(1);
240 |     unmount();
241 |     expect(callback).toHaveBeenCalledTimes(1);
242 |     expect(returnSpy).toHaveBeenCalledTimes(1);
243 |   });
244 | 
245 |   test("deps", async () => {
246 |     const callback = jest.fn((deps) => {
247 |       return new Repeater<number>(async (push) => {
248 |         for await (const [num] of deps) {
249 |           await push(num);
250 |         }
251 | 
252 |         return -1;
253 |       });
254 |     });
255 | 
256 |     const { result, rerender, waitForNextUpdate } = renderHook(
257 |       (props) => {
258 |         return useValue(callback, [props.num]);
259 |       },
260 |       { initialProps: { num: 1 } },
261 |     );
262 | 
263 |     expect(result.current).toBeUndefined();
264 |     await waitForNextUpdate();
265 |     expect(result.current).toBe(1);
266 |     rerender({ num: 2 });
267 |     expect(result.current).toBe(1);
268 |     await waitForNextUpdate();
269 |     expect(result.current).toBe(2);
270 |     rerender({ num: 3 });
271 |     expect(result.current).toBe(2);
272 |     await waitForNextUpdate();
273 |     expect(result.current).toBe(3);
274 |     expect(callback).toHaveBeenCalledTimes(1);
275 |   });
276 | });
277 | 


--------------------------------------------------------------------------------
/src/react-hooks.ts:
--------------------------------------------------------------------------------
 1 | import { useEffect, useState } from "react";
 2 | import { Push, Repeater, RepeaterBuffer, Stop } from "@repeaterjs/repeater";
 3 | 
 4 | // Repeaters are lazy, hooks are eager.
 5 | // We need to return push and stop synchronously from the useRepeater hook so
 6 | // we prime the repeater by calling next immediately.
 7 | function createPrimedRepeater<T>(
 8 |   buffer?: RepeaterBuffer,
 9 | ): [Repeater<T>, Push<T>, Stop] {
10 |   let push: Push<T>;
11 |   let stop: Stop;
12 |   const repeater = new Repeater<T>((push1, stop1) => {
13 |     push = push1;
14 |     stop = stop1;
15 |     // this value is thrown away
16 |     push(null as any);
17 |   }, buffer);
18 |   // pull and throw away the first value so the executor above runs
19 |   repeater.next();
20 |   return [repeater, push!, stop!];
21 | }
22 | 
23 | export function useRepeater<T>(
24 |   buffer?: RepeaterBuffer,
25 | ): [Repeater<T>, Push<T>, Stop] {
26 |   const [tuple] = useState(() => createPrimedRepeater<T>(buffer));
27 |   return tuple;
28 | }
29 | 
30 | export function useAsyncIter<T, TDeps extends any[]>(
31 |   callback: (deps: AsyncIterableIterator<TDeps>) => AsyncIterableIterator<T>,
32 |   deps: TDeps = ([] as unknown) as TDeps,
33 | ): AsyncIterableIterator<T> {
34 |   const [repeater, push] = useRepeater<TDeps>();
35 |   const [iter] = useState(() => callback(repeater));
36 |   useEffect(() => {
37 |     push(deps);
38 |   }, [push, ...deps]); // eslint-disable-line react-hooks/exhaustive-deps
39 | 
40 |   useEffect(
41 |     () => () => {
42 |       if (iter.return != null) {
43 |         // TODO: handle return errors
44 |         iter.return().catch();
45 |       }
46 |     },
47 |     [iter],
48 |   );
49 | 
50 |   return iter;
51 | }
52 | 
53 | export function useResult<T, TDeps extends any[]>(
54 |   callback: (deps: AsyncIterableIterator<TDeps>) => AsyncIterableIterator<T>,
55 |   deps?: TDeps,
56 | ): IteratorResult<T> | undefined {
57 |   const iter = useAsyncIter(callback, deps);
58 |   const [result, setResult] = useState<IteratorResult<T>>();
59 |   useEffect(() => {
60 |     let mounted = true;
61 |     (async () => {
62 |       try {
63 |         while (mounted) {
64 |           const result = await iter.next();
65 |           if (mounted) {
66 |             setResult(result);
67 |           }
68 | 
69 |           if (result.done) {
70 |             break;
71 |           }
72 |         }
73 |       } catch (err) {
74 |         if (mounted) {
75 |           setResult(() => {
76 |             throw err;
77 |           });
78 |         }
79 |       }
80 |     })();
81 | 
82 |     return () => {
83 |       mounted = false;
84 |     };
85 |   }, [iter]);
86 | 
87 |   return result;
88 | }
89 | 
90 | export function useValue<T, TDeps extends any[]>(
91 |   callback: (deps: AsyncIterableIterator<TDeps>) => AsyncIterableIterator<T>,
92 |   deps?: TDeps,
93 | ): T | undefined {
94 |   const result = useResult(callback, deps);
95 |   return result && result.value;
96 | }
97 | 


--------------------------------------------------------------------------------
/stories/addons.js:
--------------------------------------------------------------------------------
1 | import "@storybook/addon-actions/register";
2 | import "@storybook/addon-links/register";
3 | import "@storybook/addon-storysource/register";
4 | 


--------------------------------------------------------------------------------
/stories/config.js:
--------------------------------------------------------------------------------
 1 | import { configure } from "@storybook/react";
 2 | 
 3 | // automatically import all files ending in *.stories.js
 4 | const req = require.context(".", true, /\.stories\.js$/);
 5 | function loadStories() {
 6 |   req.keys().forEach((filename) => req(filename));
 7 | }
 8 | 
 9 | configure(loadStories, module);
10 | 


--------------------------------------------------------------------------------
/stories/react-hooks.stories.js:
--------------------------------------------------------------------------------
  1 | import React from "react"; // eslint-disable-line
  2 | import { useState } from "react";
  3 | import { storiesOf } from "@storybook/react";
  4 | import { Repeater } from "@repeaterjs/repeater";
  5 | import { useAsyncIter, useResult } from "../lib/react-hooks.esm";
  6 | 
  7 | storiesOf("useResult", module)
  8 |   .add("counter", () => {
  9 |     const result = useResult(async function*() {
 10 |       let i = 0;
 11 |       while (true) {
 12 |         yield i++;
 13 |         await new Promise((resolve) => setTimeout(resolve, 1000));
 14 |       }
 15 |     });
 16 | 
 17 |     return <div>Current value: {result && result.value}</div>;
 18 |   })
 19 |   .add("websocket", () => {
 20 |     const [socket] = useState(() => {
 21 |       return new WebSocket("wss://echo.websocket.org");
 22 |     });
 23 |     const [open] = useState(() => {
 24 |       return new Promise((resolve) => (socket.onopen = resolve));
 25 |     });
 26 |     const messages = new Repeater(async (push, stop) => {
 27 |       socket.onmessage = (ev) => push(ev.data);
 28 |       socket.onerror = () => stop(new Error("WebSocket error"));
 29 |       socket.onclose = () => stop();
 30 |       await stop;
 31 |       socket.close();
 32 |     });
 33 |     const [value, setValue] = useState("");
 34 |     const result = useResult(async function*() {
 35 |       const value = [];
 36 |       yield value;
 37 |       for await (const message of messages) {
 38 |         value.push(message);
 39 |         yield value;
 40 |       }
 41 |     });
 42 |     return (
 43 |       <div>
 44 |         <input
 45 |           type="text"
 46 |           value={value}
 47 |           onChange={(ev) => {
 48 |             setValue(ev.target.value);
 49 |           }}
 50 |           onKeyPress={(ev) => {
 51 |             if (ev.key === "Enter") {
 52 |               open.then(() => {
 53 |                 socket.send(value);
 54 |                 setValue("");
 55 |               });
 56 |             }
 57 |           }}
 58 |         />
 59 |         {result &&
 60 |           result.value.map((message, i) => <div key={i}>{message}</div>)}
 61 |       </div>
 62 |     );
 63 |   })
 64 |   .add("konami", () => {
 65 |     const konami = [
 66 |       "ArrowUp",
 67 |       "ArrowUp",
 68 |       "ArrowDown",
 69 |       "ArrowDown",
 70 |       "ArrowLeft",
 71 |       "ArrowRight",
 72 |       "ArrowLeft",
 73 |       "ArrowRight",
 74 |       "b",
 75 |       "a",
 76 |     ];
 77 |     const keys = useAsyncIter(() => {
 78 |       return new Repeater(async (push, stop) => {
 79 |         const listener = (ev) => {
 80 |           push(ev.key);
 81 |         };
 82 |         window.addEventListener("keyup", listener);
 83 |         await stop;
 84 |         window.removeEventListener("keyup", listener);
 85 |       });
 86 |     });
 87 | 
 88 |     const result = useResult(async function*() {
 89 |       let i = 0;
 90 |       yield konami[i];
 91 |       for await (const key of keys) {
 92 |         if (key === konami[i]) {
 93 |           yield `${konami[i]} (pressed)`;
 94 |           i++;
 95 |         } else {
 96 |           i = 0;
 97 |         }
 98 | 
 99 |         if (i < konami.length) {
100 |           await new Promise((resolve) => setTimeout(resolve, 100));
101 |           yield konami[i];
102 |         } else {
103 |           return "Cheats activated";
104 |         }
105 |       }
106 |     });
107 | 
108 |     if (result == null) {
109 |       return null;
110 |     } else if (result.done) {
111 |       return <div>🎉 {result.value} 🎉</div>;
112 |     }
113 | 
114 |     return <div>Next key: {result.value}</div>;
115 |   });
116 | 


--------------------------------------------------------------------------------
/stories/webpack.config.js:
--------------------------------------------------------------------------------
 1 | module.exports = function({ config }) {
 2 |   config.module.rules.push({
 3 |     test: /\.stories\.jsx?$/,
 4 |     loaders: [require.resolve("@storybook/source-loader")],
 5 |     enforce: "pre",
 6 |   });
 7 | 
 8 |   return config;
 9 | };
10 | 


--------------------------------------------------------------------------------
/tsconfig.json:
--------------------------------------------------------------------------------
 1 | {
 2 | 	"files": [
 3 | 		"src/react-hooks.ts"
 4 | 	],
 5 |   "compilerOptions": {
 6 |     /* Basic Options */
 7 |     "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
 8 |     // "module": "es2015",                    /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
 9 |     "lib": ["esnext", "dom"],                 /* Specify library files to be included in the compilation. */
10 |     // "allowJs": true,                       /* Allow javascript files to be compiled. */
11 |     // "checkJs": true,                       /* Report errors in .js files. */
12 |     // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
13 |     "declaration": true,                      /* Generates corresponding '.d.ts' file. */
14 |     // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
15 |     // "sourceMap": true,                     /* Generates corresponding '.map' file. */
16 |     // "outFile": "./",                       /* Concatenate and emit output to single file. */
17 |     // "outDir": "./lib",                     /* Redirect output structure to the directory. */
18 |     // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
19 |     // "composite": true,                     /* Enable project compilation */
20 |     // "removeComments": true,                /* Do not emit comments to output. */
21 |     // "noEmit": true,                        /* Do not emit outputs. */
22 |     // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
23 |     "downlevelIteration": true,               /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
24 |     // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
25 | 
26 |     /* Strict Type-Checking Options */
27 |     "strict": true,                           /* Enable all strict type-checking options. */
28 |     // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
29 |     // "strictNullChecks": true,              /* Enable strict null checks. */
30 |     // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
31 |     // "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
32 |     // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
33 |     // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
34 |     // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */
35 | 
36 |     /* Additional Checks */
37 |     // "noUnusedLocals": true,                /* Report errors on unused locals. */
38 |     // "noUnusedParameters": true,            /* Report errors on unused parameters. */
39 |     // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
40 |     // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */
41 | 
42 |     /* Module Resolution Options */
43 |     "moduleResolution": "node",               /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
44 |     // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
45 |     // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
46 |     // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
47 |     // "typeRoots": [],                       /* List of folders to include type definitions from. */
48 |     // "types": [],                           /* Type declaration files to be included in compilation. */
49 |     // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
50 |     "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
51 |     // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
52 | 
53 |     /* Source Map Options */
54 |     // "sourceRoot": "",                      /* Specify the location where debugger should locate TypeScript files instead of source locations. */
55 |     // "mapRoot": "",                         /* Specify the location where debugger should locate map files instead of generated locations. */
56 |     // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
57 |     // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
58 | 
59 |     /* Experimental Options */
60 |     // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
61 |     // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
62 |   }
63 | }
64 | 


--------------------------------------------------------------------------------