# Tree Shaking _tree shaking_ 是一个术语，通常用于描述移除 JavaScript 上下文中的未引用代码\(dead-code\)。它依赖于 ES2015 模块系统中的 [静态结构特性](http://exploringjs.com/es6/ch_modules.html#static-module-structure)，例如[`import`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import)和[`export`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/export)。这个术语和概念实际上是兴起于 ES2015 模块打包工具[rollup](https://github.com/rollup/rollup)。 ``` npm install --save-dev uglifyjs-webpack-plugin ``` **webpack.config.js** ``` const path = require('path'); + const UglifyJSPlugin = require('uglifyjs-webpack-plugin'); module.exports = { entry: './src/index.js', output: { filename: 'bundle.js', path: path.resolve(__dirname, 'dist') - } + }, + plugins: [ + new UglifyJSPlugin() + ] }; ``` [https://juejin.im/entry/58627bb0570c350069511d59](https://juejin.im/entry/58627bb0570c350069511d59 "参考链接")