javascript - 摇树不适用于 webpack 4 和 semantic-ui-react

Question

我只从 semantic-ui-react 导入一个组件

import { Button as SemanticButton} from 'semantic-ui-react';

但是在运行 webpack -p 之后，我在 bundle 中看到了来自 Semantic UI 的所有组件，它的大小超过 300KB(如果没有 Semantic UI，大约 30KB)。 我安装了所有最新版本:webpack@4.14.0； semantic-ui-react@0.81.3

这是我的 webpack.config.js

module.exports = {
  entry: './src/index.js',
  resolve: {
    modules: [
      path.resolve('./'),
      'node_modules',
    ],
    extensions: ['*', '.js', '.jsx', '.css', '.less'],
  },
  output: {
    filename: 'main.js',
    path: path.resolve(__dirname, 'dist'),
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: {
          loader: 'babel-loader',
        },
      },
    ],
  },
  externals: {
    react: {
      root: 'React',
      commonjs: 'react',
      commonjs2: 'react',
      amd: 'React',
    },
    'react-dom': {
      root: 'ReactDOM',
      commonjs: 'react-dom',
      commonjs2: 'react-dom',
      amd: 'ReactDOM',
    },
    'prop-types': {
      root: 'PropTypes',
      commonjs: 'prop-types',
      commonjs2: 'prop-types',
      amd: 'PropTypes',
    },
  },
};

我做错了什么吗？如何使 tree shaking 与 semantic-ui-react 一起工作？我不想看到 bundle 中未使用的组件。

Answer 1

这个问题的解决方案变得相当简单。你只需要正确配置 Babel 即可。

Simply specifying "modules": false in your babel-preset-env config gets Babel to behave how we want, which allows webpack to analyze your dependency tree and shake off those unused dependencies. Furthermore, this process doesn't cause compatibility issues, as webpack ends up converting your code into a format that's widely compatible, anyway.

所以 .babelrc 可以看起来像这样:

{
  "presets": [
    ["env", {
      "modules": false
    }]
  ]
}

Source