typescript-react-webpack4 起手与踩坑

前言

webpack4正式版发布也有一段时间了, 为了从实际中感觉变化, 因而以typescript, react, 结合以前翻译的一篇文章webpack-4.0更新日志（翻译）, 搭建一个可供项目使用的框架.

项目情况

github

前往

项目已使用

• webpack-4
• typescript
• react
• react-router-4
• component hot reload
• async component
• css-module(import .(s)css auto generate .(s)css.d.ts)
• svg icon

待添加

• state management (Redux or Mobx)
• UI lib (Element-React)
• jest

主要库及版本

• webpack --------- 4.1.1
• typescript -------- 2.7.2
• react ------------ 16.2.0
• react-router-dom -- 4.2.2
• react-hot-loader --- 4.0.0
• ......
• node ------------- 8.9.4

坑

我是由另外一个项目升级过来的, 由于原项目没用babel, 直接以ts-loader转.

原项目涉及到配置变化的库及版本

• webpack --------- 4.1.1
• react-hot-loader --- 3.1.3

原配置:

// tsconfig.json
{
  "compilerOptions": {
    "target": "es5",
    "module": "es2015",
    "moduleResolution": "node",
    ....
  }
}
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// webpack.config.js
{
    test: /\.(ts(x?)|js(x?))$/,
    exclude: /node_modules/,
    rules: [
      {
        loader: 'react-hot-loader/webpack',
      },
      {
        loader: 'ts-loader',
        options: {
          transpileOnly: true
        }
    }
}
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Module not found: Error: Can't resolve 'react-hot-loader/webpack' in '/Users/jackple/Documents/react/ts-react-webpack4' 复制代码

果真跑不通, 符合心理预期!😂😂😂😂

查看node_modules里面的react-hot-loader, 对比原项目node_modules的react-hot-loader, 文件结构改了很多, 看4.0.0的源码, 也再也不有webpack目录, 并且代码中有这么一段:

throw new Error('React Hot Loader: You are erroneously trying to use a Babel plugin ' + 'as a Webpack loader. We recommend that you use Babel, ' + 'remove "react-hot-loader/babel" from the "loaders" section ' + 'of your Webpack configuration, and instead add ' + '"react-hot-loader/babel" to the "plugins" section of your .babelrc file. ' + 'If you prefer not to use Babel, replace "react-hot-loader/babel" with ' + '"react-hot-loader/webpack" in the "loaders" section of your Webpack configuration. ');
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提示信息与实际不符, 估计提示没改过来, 仍是用babel吧(其实它的README也是建议用babel), 省得挣扎!!

按照react-hot-loader官方推荐作法以及demo

When using TypeScript, Babel is not required, but React Hot Loader will not work without it. Just add babel-loader into your Webpack configuration, with React Hot Loader plugin.

{
  test: /\.tsx?$/,
  use: [
    {
      loader: 'babel-loader',
      options: {
        babelrc: true,
        plugins: ['react-hot-loader/babel'],
      },
    },
    'ts-loader', // (or awesome-typescript-loader)
  ],
}
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You also have to modify your tsconfig.json:

// tsconfig.json
{
  "module": "commonjs",
  "target": "es6"
}
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// xxx.tsx
import { hot } from 'react-hot-loader'
...
export default hot(module)(Component)
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1. 首先是react-hot-loader/babel, 不管是按官方推荐配置, 仍是写在.babelrc, 以上二者都加上环境判断, 开发环境没问题, 但是打包出来的生产环境代码看起来怪怪的:

...
default = i, u = r(4).
default, s = r(4).leaveModule, u && (u.register(l, "Error", "/Users/jackple/Documents/react/ts-react-webpack4/src/components/Error/index.tsx"), u.register(i, "default", "/Users/jackple/Documents/react/ts-react-webpack4/src/components/Error/index.tsx"), s(e))
}).call(this, r(12)(e))
...
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怎么看都不合理呀! 为何会出来个人本地源文件路径! 本地开nginx调试生产环境代码, 虽然能跑, 不过, 这不是我想要的!

最后, 这部分的处理结果是把react-hot-loader/babel删除之! 再将tsx接受hot reload还原为旧式写法:

import { AppContainer } from 'react-hot-loader'

import AppRouter from './router'

const render = Component => {
    ReactDOM.render(
        <AppContainer>
            <Component />
        </AppContainer>,
        document.getElementById('app') as HTMLElement
    )
}

render(AppRouter)

// Hot Module Replacement API
if (module.hot) {
    module.hot.accept(['router'], () => {
        import('./router').then(mod => render(mod.default))
    })
}

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2. 再者是为配合webpack4的代码分割(dynamic import), 须要把tsconfig.json中的module置为esnext(主要是为了让typescript不编译import), 不知道是否是我配置失误, 显示如下错误:

ERROR in ./src/index.tsx
Module build failed: SyntaxError: 'import' and 'export' may only appear at the top level (14:8)

  12 | if (module.hot) {
  13 |     module.hot.accept(['router'], () => {
> 14 |         import('./router').then(mod => render(mod.default));
     |         ^
  15 |     });
  16 | }
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不是说好的支持import语法了咩? 最后仍是要加上syntax-dynamic-import的babel插件

3. css module提取

new ExtractTextPlugin({
    filename: assetsPath('css/[name].[contenthash].css')
})
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bootstrap:74 Uncaught (in promise) TypeError: Cannot read property 'call' of undefined
    at i (bootstrap:74)
    at Object.31 (index.css:1)
    at i (bootstrap:74)
    at Object.32 (index.css?f62f:2)
    at i (bootstrap:74)
    at Object.52 (index.tsx:3)
    at i (bootstrap:74)
    at index.tsx:9
    at <anonymous>
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异步组件的css提取问题, 暂以提取全部css到一个文件中了结, 即:

new ExtractTextPlugin({
    allChunks: true,
    filename: assetsPath('css/[name].[contenthash].css')
})
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过程曲折, 还有一些问题没写上, 具体请参考项目...

若是你们有更好的解决方案, 也欢迎评论或提issue