├── .npmignore ├── .gitignore ├── .travis.yml ├── .babelrc.js ├── .editorconfig ├── rollup.config.js ├── index.html ├── LICENSE ├── package.json ├── readme.md ├── example.js └── src └── LazyList.js /.npmignore: -------------------------------------------------------------------------------- 1 | /node_modules 2 | /example.* 3 | /index.html 4 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | /dist 2 | /node_modules 3 | /example.build.js 4 | package-lock.json 5 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | language: node_js 2 | sudo: false 3 | node_js: 4 | - 10 5 | - 8 6 | - 7 7 | - 6 8 | -------------------------------------------------------------------------------- /.babelrc.js: -------------------------------------------------------------------------------- 1 | module.exports = { 2 | presets: [ 3 | ['@babel/preset-env', { 4 | loose: true, 5 | modules: process.env.EXAMPLE === '1' ? 'commonjs' : false, 6 | }], 7 | '@babel/preset-react', 8 | ], 9 | }; 10 | -------------------------------------------------------------------------------- /.editorconfig: -------------------------------------------------------------------------------- 1 | # EditorConfig helps developers define and maintain consistent 2 | # coding styles between different editors and IDEs 3 | # editorconfig.org 4 | 5 | root = true 6 | 7 | [*] 8 | end_of_line = lf 9 | charset = utf-8 10 | trim_trailing_whitespace = true 11 | insert_final_newline = true 12 | indent_style = space 13 | indent_size = 2 14 | 15 | [*.md] 16 | trim_trailing_whitespace = false 17 | -------------------------------------------------------------------------------- /rollup.config.js: -------------------------------------------------------------------------------- 1 | import babel from '@rollup/plugin-babel' 2 | 3 | const meta = require('./package.json') 4 | 5 | export default { 6 | input: './src/LazyList.js', 7 | output: [ 8 | { format: 'cjs', file: meta.main, exports: 'default' }, 9 | { format: 'es', file: meta.module } 10 | ], 11 | 12 | external: Object.keys(meta.dependencies) 13 | .concat(Object.keys(meta.peerDependencies)), 14 | plugins: [ 15 | babel({ babelHelpers: 'bundled' }) 16 | ] 17 | } 18 | -------------------------------------------------------------------------------- /index.html: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | react-list Lazy Load example 6 | 11 | 12 | 13 |

react-list-lazy-load example

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21 | 22 | 23 | 24 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | The MIT License (MIT) 2 | 3 | Copyright (c) 2016 Renée Kooi 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "react-list-lazy-load", 3 | "version": "1.1.2", 4 | "description": "Lazy loading wrapper for react-list.", 5 | "main": "dist/react-list-lazy-load.js", 6 | "module": "dist/react-list-lazy-load.es.js", 7 | "repository": "u-wave/react-list-lazy-load", 8 | "scripts": { 9 | "build": "rollup -c", 10 | "example": "cross-env EXAMPLE=1 browserify example.js -t babelify --debug -r ./:react-list-lazy-load -o example.build.js", 11 | "test": "standard example.js src/**/*.js", 12 | "prepare": "npm run build" 13 | }, 14 | "keywords": [], 15 | "author": "Renée Kooi ", 16 | "license": "MIT", 17 | "dependencies": { 18 | "prop-types": "^15.7.2" 19 | }, 20 | "devDependencies": { 21 | "@babel/core": "^7.12.17", 22 | "@babel/plugin-transform-modules-commonjs": "^7.12.13", 23 | "@babel/preset-env": "^7.12.17", 24 | "@babel/preset-react": "^7.12.13", 25 | "@rollup/plugin-babel": "^5.3.0", 26 | "babelify": "^10.0.0", 27 | "browserify": "^17.0.0", 28 | "cross-env": "^7.0.3", 29 | "react": "^16.14.0", 30 | "react-dom": "^16.14.0", 31 | "react-list": "^0.8.16", 32 | "rollup": "^2.0.0", 33 | "standard": "^14.3.4" 34 | }, 35 | "peerDependencies": { 36 | "react": "^0.14.0 || ^15.0.0 || ^16.0.0", 37 | "react-dom": "^0.14.0 || ^ 15.0.0 || ^16.0.0", 38 | "react-list": "^0.7.0 || ^0.8.0 < 0.8.10 || ^0.8.10" 39 | } 40 | } 41 | -------------------------------------------------------------------------------- /readme.md: -------------------------------------------------------------------------------- 1 | # react-list-lazy-load 2 | 3 | > **Unmaintained**. Consider using [react-virtual](https://github.com/tanstack/virtual). 4 | 5 | Lazy Loading wrapper for [React-List](https://github.com/orgsync/react-list). 6 | 7 | This component works for finite collections only. If you have a large list of a 8 | known size that you do not want to load all at once, this component allows 9 | loading pages once the user scrolls near them. It does **not** implement 10 | infinite scrolling. 11 | 12 | [![npm][npm-image]][npm-url] 13 | [![travis][travis-image]][travis-url] 14 | [![size][size-image]][size-url] 15 | 16 | [npm-image]: https://img.shields.io/npm/v/react-list-lazy-load.svg?style=flat-square 17 | [npm-url]: https://www.npmjs.com/package/react-list-lazy-load 18 | [travis-image]: https://img.shields.io/travis/u-wave/react-list-lazy-load.svg?style=flat-square 19 | [travis-url]: https://travis-ci.org/u-wave/react-list-lazy-load 20 | [size-image]: https://img.shields.io/bundlephobia/minzip/react-list-lazy-load.svg?style=flat-square 21 | [size-url]: https://bundlephobia.com/result?p=react-list-lazy-load 22 | 23 | ## Installation 24 | 25 | ```bash 26 | npm install --save react-list-lazy-load 27 | ``` 28 | 29 | ## Usage 30 | 31 | [Demo](https://u-wave.github.io/react-list-lazy-load) - [Demo source code](./example.js) 32 | 33 | You wrap it around a `` element to :sparkles: magically :sparkles: 34 | add lazy loading hooks: 35 | 36 | ```js 37 | import ReactList from 'react-list'; 38 | import LazyLoading from 'react-list-lazy-load'; 39 | 40 | const MyList = ({ items, onRequestPage }) => ( 41 | 46 | ( 48 |

{items[idx]}

49 | )} 50 | type="uniform" 51 | length={items.length} 52 | /> 53 | 54 | ); 55 | ``` 56 | 57 | ## API 58 | 59 | ### `items={Array}` 60 | 61 | An array of the items you're showing. This is used to determine when to load a 62 | page. If the user scrolls close to a `null` item in this array, or outside of 63 | array bounds, a new page will be loaded. 64 | 65 | I.e., a `null` item is regarded as an unloaded item. 66 | 67 | ### `length={Number}` 68 | 69 | The total amount of items, on all "pages". Defaults to 70 | 71 | ### `pageSize={Number}` 72 | 73 | Amount of items on a page. This is used to determine which page to load. 74 | Defaults to 25 (rather arbitrarily). 75 | 76 | ### `loadMargin={Number}` 77 | 78 | When to start loading the next page. The next page will be loaded when the user 79 | scrolls within `loadMargin` items from an unloaded item. You'll want to change 80 | this depending on the size of your items. If your items are super small, you 81 | should pick a larger `loadMargin`, but if they are rather large, you might be 82 | good with a margin of like 1 or 2 items. 83 | 84 | Defaults to 5. 85 | 86 | ### `onRequestPage={function(page, cb)}` 87 | 88 | Callback to load a page. This only tells you to load a new page--you should 89 | merge it into the `items` prop yourself. 90 | 91 | ## Licence 92 | 93 | [MIT](./LICENSE) 94 | -------------------------------------------------------------------------------- /example.js: -------------------------------------------------------------------------------- 1 | import React from 'react' 2 | import ReactDOM from 'react-dom' 3 | import PropTypes from 'prop-types' 4 | // LazyList wraps around ReactList--so we need both! 5 | import LazyList from 'react-list-lazy-load' 6 | import ReactList from 'react-list' 7 | 8 | const randBetween = (min, max) => 9 | Math.floor(min + (Math.random() * (max - min))) 10 | 11 | // Utility to create arrays with test data 12 | const array = (len, val = () => null) => { 13 | const arr = [] 14 | for (let i = 0; i < len; i++) { 15 | arr.push(val(i)) 16 | } 17 | return arr 18 | } 19 | 20 | function mergePage (items, newItems, offset) { 21 | const merged = items.slice() 22 | newItems.forEach((item, idx) => { 23 | merged[idx + offset] = item 24 | }) 25 | return merged 26 | } 27 | 28 | class App extends React.Component { 29 | constructor (props) { 30 | super(props) 31 | this.state = { 32 | items: array(25, (i) => `item #${i}`) 33 | } 34 | 35 | this.handleRequestPage = this.handleRequestPage.bind(this) 36 | } 37 | 38 | // Simulate a network request for `limit` items 39 | fetch (page, cb) { 40 | const { minLoadTime, maxLoadTime, pageSize } = this.props 41 | setTimeout(() => { 42 | // Generate a new page of items 43 | const data = array(pageSize, (i) => `item #${(page * pageSize) + i}`) 44 | 45 | cb(data) 46 | }, randBetween(minLoadTime, maxLoadTime)) 47 | } 48 | 49 | handleRequestPage (page, cb) { 50 | const { pageSize } = this.props 51 | 52 | // Simulate a network request or other async operation 53 | this.fetch(page, (data) => { 54 | // Merge the new page into the current `items` collection and rerender 55 | this.setState({ 56 | items: mergePage(this.state.items, data, page * pageSize) 57 | }) 58 | 59 | // Tell LazyList that the page was loaded 60 | cb() 61 | }) 62 | } 63 | 64 | render () { 65 | const { totalItems } = this.props 66 | const { items } = this.state 67 | return ( 68 | 74 | ( 78 | // If `items[index] == null`, the page is still being loaded. 79 | items[index] != null ? ( 80 |

81 | #{index} 82 | {items[index]} 83 |

84 | ) : ( 85 |

Loading …

86 | ) 87 | )} 88 | /> 89 | 90 | ) 91 | } 92 | } 93 | 94 | App.propTypes = { 95 | pageSize: PropTypes.number.isRequired, 96 | totalItems: PropTypes.number.isRequired, 97 | minLoadTime: PropTypes.number.isRequired, 98 | maxLoadTime: PropTypes.number.isRequired 99 | } 100 | 101 | ReactDOM.render( 102 | , 108 | document.getElementById('example') 109 | ) 110 | -------------------------------------------------------------------------------- /src/LazyList.js: -------------------------------------------------------------------------------- 1 | import React from 'react' 2 | import PropTypes from 'prop-types' 3 | 4 | const proxyMethods = [ 5 | 'getOffset', 6 | 'getScroll', 7 | 'setScroll', 8 | 'getViewportSize', 9 | 'getScrollSize', 10 | 'getStartAndEnd', 11 | 'getItemSizeAndItemsPerRow', 12 | 'getSpaceBefore', 13 | 'getSizeOf', 14 | 'scrollTo', 15 | 'scrollAround', 16 | 'getVisibleRange' 17 | ] 18 | 19 | function requestPage (call, page, cb) { 20 | const promise = call(page, cb) 21 | if (promise && promise.then) { 22 | promise 23 | .then((res) => cb(null, res)) 24 | .then(null, cb) 25 | } 26 | } 27 | 28 | /** 29 | * Like `.slice`, but doesn't care about array bounds. 30 | * 31 | * [0, 1].slice(1, 3) === [1] 32 | * eagerSlice([0, 1], 1, 3) === [1, undefined, undefined] 33 | */ 34 | function eagerSlice (list, start, end) { 35 | const sliced = [] 36 | for (let i = start; i < end; i++) { 37 | sliced.push(list[i]) 38 | } 39 | return sliced 40 | } 41 | 42 | /** 43 | * Adds simple lazy loading to react-list. 44 | */ 45 | class LazyList extends React.Component { 46 | constructor (props) { 47 | super(props) 48 | 49 | this._list = null 50 | this._loadingPages = {} 51 | this.updateFrame = this.updateFrame.bind(this) 52 | } 53 | 54 | componentDidMount () { 55 | this.updateScrollParent() 56 | this.updateFrame() 57 | } 58 | 59 | componentDidUpdate () { 60 | this.updateScrollParent() 61 | this.updateFrame() 62 | } 63 | 64 | updateScrollParent () { 65 | const prev = this.scrollParent 66 | const list = this.getList() 67 | this.scrollParent = list.scrollParent 68 | 69 | if (prev === this.scrollParent) { 70 | return 71 | } 72 | if (prev) { 73 | prev.removeEventListener('scroll', this.updateFrame) 74 | } 75 | if (this.props.onRequestPage) { 76 | this.scrollParent.addEventListener('scroll', this.updateFrame) 77 | } 78 | } 79 | 80 | getList () { 81 | return this._list 82 | } 83 | 84 | isLoadingPage (page) { 85 | return !!this._loadingPages[page] 86 | } 87 | 88 | itemNeedsLoad (idx) { 89 | const { items, pageSize } = this.props 90 | const page = Math.floor(idx / pageSize) 91 | return items[idx] != null || this.isLoadingPage(page) 92 | } 93 | 94 | updateFrame () { 95 | const { 96 | pageSize, loadMargin, 97 | items, length, 98 | onRequestPage 99 | } = this.props 100 | 101 | // Item range that should be loaded right about now. 102 | let [topItem, bottomItem] = this.getVisibleRange() 103 | 104 | if (topItem === undefined || bottomItem === undefined) { 105 | return 106 | } 107 | 108 | topItem = Math.max(topItem - loadMargin, 0) 109 | bottomItem = Math.min(bottomItem + loadMargin, length) 110 | 111 | const almostVisibleItems = eagerSlice(items, topItem, bottomItem) 112 | 113 | const unloadedPages = almostVisibleItems.reduce((pages, item, idx) => { 114 | if (item == null) { 115 | const page = Math.floor((topItem + idx) / pageSize) 116 | if (!this.isLoadingPage(page) && pages.indexOf(page) === -1) { 117 | return [...pages, page] 118 | } 119 | } 120 | return pages 121 | }, []) 122 | 123 | unloadedPages.forEach((page) => { 124 | this._loadingPages[page] = true 125 | requestPage(onRequestPage, page, () => { 126 | // Always delete after completion. If there was an error, we can retry 127 | // later. If there wasn't, we don't need to keep this around :) 128 | delete this._loadingPages[page] 129 | }) 130 | }) 131 | } 132 | 133 | render () { 134 | return React.cloneElement(this.props.children, { 135 | ref: (list) => { 136 | this._list = list 137 | } 138 | }) 139 | } 140 | } 141 | 142 | if (process.env.NODE_ENV !== 'production') { 143 | LazyList.propTypes = { 144 | /** 145 | * Total amount of items, on all pages. 146 | */ 147 | length: PropTypes.number.isRequired, 148 | /** 149 | * Items per page. 150 | */ 151 | pageSize: PropTypes.number, 152 | /** 153 | * When to begin loading the next page. 154 | */ 155 | loadMargin: PropTypes.number, 156 | /** 157 | * Loaded items. NULLs in this array indicate unloaded items. 158 | */ 159 | items: PropTypes.array, 160 | 161 | /** 162 | * Callback to begin loading a page. 163 | */ 164 | onRequestPage: PropTypes.func.isRequired 165 | } 166 | } 167 | 168 | LazyList.defaultProps = { 169 | pageSize: 25, 170 | loadMargin: 5 171 | } 172 | 173 | proxyMethods.forEach((name) => { 174 | LazyList.prototype[name] = function (...args) { 175 | return this.getList()[name](...args) 176 | } 177 | }) 178 | 179 | export default LazyList 180 | --------------------------------------------------------------------------------