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<!DOCTYPE HTML> <html lang="en" > <head> <meta charset="UTF-8"> <meta content="text/html; charset=utf-8" http-equiv="Content-Type"> <title>Plugins · Vuex</title> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta name="description" content=""> <meta name="generator" content="GitBook 3.2.3"> <link rel="stylesheet" href="../gitbook/style.css"> <link rel="stylesheet" href="../gitbook/gitbook-plugin-prism/prism.css"> <link rel="stylesheet" href="../gitbook/gitbook-plugin-search/search.css"> <link rel="stylesheet" href="../gitbook/gitbook-plugin-theme-vuejs/vue.css"> <meta name="HandheldFriendly" content="true"/> <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no"> <meta name="apple-mobile-web-app-capable" content="yes"> <meta name="apple-mobile-web-app-status-bar-style" content="black"> <link rel="apple-touch-icon-precomposed" sizes="152x152" href="../gitbook/images/apple-touch-icon-precomposed-152.png"> <link rel="shortcut icon" href="../gitbook/images/favicon.ico" type="image/x-icon"> <link rel="next" href="strict.html" /> <link rel="prev" href="structure.html" /> </head> <body> <div class="book"> <div class="book-summary"> <div id="book-search-input" role="search"> <input type="text" placeholder="Type to search" /> </div> <nav role="navigation"> <script async type="text/javascript" src="//cdn.carbonads.com/carbon.js?zoneid=1673&serve=C6AILKT&placement=vuejs" id="_carbonads_js"></script> <ul class="summary"> <li class="chapter " data-level="1.1" data-path="./"> <a href="./"> Introduction </a> </li> <li class="chapter " data-level="1.2" > <a target="_blank" href="https://github.com/vuejs/vuex/releases"> Release Notes </a> </li> <li class="chapter " data-level="1.3" data-path="installation.html"> <a href="installation.html"> Installation </a> </li> <li class="chapter " data-level="1.4" data-path="intro.html"> <a href="intro.html"> What is Vuex? </a> </li> <li class="chapter " data-level="1.5" data-path="getting-started.html"> <a href="getting-started.html"> Getting Started </a> </li> <li class="chapter " data-level="1.6" data-path="core-concepts.html"> <a href="core-concepts.html"> Core Concepts </a> <ul class="articles"> <li class="chapter " data-level="1.6.1" data-path="state.html"> <a href="state.html"> State </a> </li> <li class="chapter " data-level="1.6.2" data-path="getters.html"> <a href="getters.html"> Getters </a> </li> <li class="chapter " data-level="1.6.3" data-path="mutations.html"> <a href="mutations.html"> Mutations </a> </li> <li class="chapter " data-level="1.6.4" data-path="actions.html"> <a href="actions.html"> Actions </a> </li> <li class="chapter " data-level="1.6.5" data-path="modules.html"> <a href="modules.html"> Modules </a> </li> </ul> </li> <li class="chapter " data-level="1.7" data-path="structure.html"> <a href="structure.html"> Application Structure </a> </li> <li class="chapter active" data-level="1.8" data-path="plugins.html"> <a href="plugins.html"> Plugins </a> </li> <li class="chapter " data-level="1.9" data-path="strict.html"> <a href="strict.html"> Strict Mode </a> </li> <li class="chapter " data-level="1.10" data-path="forms.html"> <a href="forms.html"> Form Handling </a> </li> <li class="chapter " data-level="1.11" data-path="testing.html"> <a href="testing.html"> Testing </a> </li> <li class="chapter " data-level="1.12" data-path="hot-reload.html"> <a href="hot-reload.html"> Hot Reloading </a> </li> <li class="chapter " data-level="1.13" data-path="api.html"> <a href="api.html"> API Reference </a> </li> <li class="divider"></li> <li> <a href="https://www.gitbook.com" target="blank" class="gitbook-link"> Published with GitBook </a> </li> </ul> </nav> </div> <div class="book-body"> <div class="body-inner"> <div class="book-header" role="navigation">  <h1> <a href="." >Plugins</a> </h1> </div> <div class="page-wrapper" tabindex="-1" role="main"> <div class="page-inner"> <div id="book-search-results"> <div class="search-noresults"> <section class="normal markdown-section"> <h1 id="plugins">Plugins</h1> Vuex stores accept the <code>plugins</code> option that exposes hooks for each mutation. A Vuex plugin is simply a function that receives the store as the only argument: <pre class="language-"><code class="lang-js">const myPlugin = store => { // called when the store is initialized store.subscribe((mutation, state) => { // called after every mutation. // The mutation comes in the format of `{ type, payload }`. }) } </code></pre> And can be used like this: <pre class="language-"><code class="lang-js">const store = new Vuex.Store({ // ... plugins: [myPlugin] }) </code></pre> <h3 id="committing-mutations-inside-plugins">Committing Mutations Inside Plugins</h3> Plugins are not allowed to directly mutate state - similar to your components, they can only trigger changes by committing mutations. By committing mutations, a plugin can be used to sync a data source to the store. For example, to sync a websocket data source to the store (this is just a contrived example, in reality the <code>createPlugin</code> function can take some additional options for more complex tasks): <pre class="language-"><code class="lang-js">export default function createWebSocketPlugin (socket) { return store => { socket.on('data', data => { store.commit('receiveData', data) }) store.subscribe(mutation => { if (mutation.type === 'UPDATE_DATA') { socket.emit('update', mutation.payload) } }) } } </code></pre> <pre class="language-"><code class="lang-js">const plugin = createWebSocketPlugin(socket) const store = new Vuex.Store({ state, mutations, plugins: [plugin] }) </code></pre> <h3 id="taking-state-snapshots">Taking State Snapshots</h3> Sometimes a plugin may want to receive "snapshots" of the state, and also compare the post-mutation state with pre-mutation state. To achieve that, you will need to perform a deep-copy on the state object: <pre class="language-"><code class="lang-js">const myPluginWithSnapshot = store => { let prevState = _.cloneDeep(store.state) store.subscribe((mutation, state) => { let nextState = _.cloneDeep(state) // compare `prevState` and `nextState`... // save state for next mutation prevState = nextState }) } </code></pre> Plugins that take state snapshots should be used only during development. When using webpack or Browserify, we can let our build tools handle that for us: <pre class="language-"><code class="lang-js">const store = new Vuex.Store({ // ... plugins: process.env.NODE_ENV !== 'production' ? [myPluginWithSnapshot] : [] }) </code></pre> The plugin will be used by default. For production, you will need <a href="https://webpack.js.org/plugins/define-plugin/" target="_blank">DefinePlugin</a> for webpack or <a href="https://github.com/hughsk/envify" target="_blank">envify</a> for Browserify to convert the value of <code>process.env.NODE_ENV !== 'production'</code> to <code>false</code> for the final build. <h3 id="built-in-logger-plugin">Built-in Logger Plugin</h3> <blockquote> If you are using <a href="https://github.com/vuejs/vue-devtools" target="_blank">vue-devtools</a> you probably don't need this. </blockquote> Vuex comes with a logger plugin for common debugging usage: <pre class="language-"><code class="lang-js">import createLogger from 'vuex/dist/logger' const store = new Vuex.Store({ plugins: [createLogger()] }) </code></pre> The <code>createLogger</code> function takes a few options: <pre class="language-"><code class="lang-js">const logger = createLogger({ collapsed: false, // auto-expand logged mutations filter (mutation, stateBefore, stateAfter) { // returns `true` if a mutation should be logged // `mutation` is a `{ type, payload }` return mutation.type !== "aBlacklistedMutation" }, transformer (state) { // transform the state before logging it. // for example return only a specific sub-tree return state.subTree }, mutationTransformer (mutation) { // mutations are logged in the format of `{ type, payload }` // we can format it any way we want. return mutation.type }, logger: console, // implementation of the `console` API, default `console` }) </code></pre> The logger file can also be included directly via a <code><script></code> tag, and will expose the <code>createVuexLogger</code> function globally. Note the logger plugin takes state snapshots, so use it only during development. </section> </div> <div class="search-results"> <div class="has-results"> <h1 class="search-results-title"> results matching ""</h1> <ul class="search-results-list"></ul> </div> <div class="no-results"> <h1 class="search-results-title">No results matching ""</h1> </div> </div> </div> </div> </div> <script src="//m.servedby-buysellads.com/monetization.js" type="text/javascript"></script> <div class="bsa-cpc"></div> <script> (function(){ if(typeof _bsa !== 'undefined' && _bsa) { _bsa.init('default', 'CKYD62QM', 'placement:vuejsorg', { target: '.bsa-cpc', align: 'horizontal', disable_css: 'true' }); } })(); </script> </div> <a href="structure.html" class="navigation navigation-prev " aria-label="Previous page: Application Structure"> </a> <a href="strict.html" class="navigation navigation-next " aria-label="Next page: Strict Mode"> </a> </div> <script> var gitbook = gitbook || []; gitbook.push(function() { gitbook.page.hasChanged({"page":{"title":"Plugins","level":"1.8","depth":1,"next":{"title":"Strict Mode","level":"1.9","depth":1,"path":"strict.md","ref":"strict.md","articles":[]},"previous":{"title":"Application Structure","level":"1.7","depth":1,"path":"structure.md","ref":"structure.md","articles":[]},"dir":"ltr"},"config":{"plugins":["edit-link","prism","-highlight","github","-highlight","github"],"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"prism":{},"github":{"url":"https://github.com/vuejs/vuex/"},"livereload":{},"search":{},"theme-vuejs":{},"lunr":{"maxIndexSize":1000000,"ignoreSpecialCharacters":false},"sharing":{"facebook":false,"twitter":false,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"edit-link":{"label":"Edit This Page","base":"https://github.com/vuejs/vuex/tree/dev/docs"},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false}},"theme":"default","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"README.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"title":"Vuex","language":"en","links":{"sharing":{"facebook":false,"twitter":false}},"gitbook":"2.x.x"},"file":{"path":"plugins.md","mtime":"2018-02-17T07:20:49.000Z","type":"markdown"},"gitbook":{"version":"3.2.3","time":"2018-03-02T20:43:43.208Z"},"basePath":".","book":{"language":"en"}}); }); </script> </div> <script src="../gitbook/gitbook.js"></script> <script src="../gitbook/theme.js"></script> <script src="../gitbook/gitbook-plugin-edit-link/plugin.js"></script> <script src="../gitbook/gitbook-plugin-github/plugin.js"></script> <script src="../gitbook/gitbook-plugin-livereload/plugin.js"></script> <script src="../gitbook/gitbook-plugin-search/search-engine.js"></script> <script src="../gitbook/gitbook-plugin-search/search.js"></script> <script src="../gitbook/gitbook-plugin-lunr/lunr.min.js"></script> <script src="../gitbook/gitbook-plugin-lunr/search-lunr.js"></script> <script src="../gitbook/gitbook-plugin-sharing/buttons.js"></script> </body> </html>