webpack4 with Babel, React, CSS Module

• 这节主要讲下babel, react, css module的简单引入，后续会根据需要再来修改，我们先做一个版本

首先，看下需要装哪些包，都是干什么的

"dependencies": {

    "react": "^16.8.1", //react package

    "react-dom": "^16.8.1",//the entry point to the DOM and server renderers for React

    "webpack": "^4.29.0",

    // polyfill: you can use Promise, WeakMap,Array.from,Object.assign,Array.includes..

    // this is a polyfill, we need it to be a dependency

    "@babel/polyfill": "^7.2.5"

  },

  "devDependencies": {

    //Compile object rest and spread to ES5

    "@babel/plugin-proposal-object-rest-spread": "^7.3.2",

// re-use of Babel's injected helper code to save on codesize.

    "@babel/plugin-transform-runtime": "^7.2.0",

    //a library that contain's Babel modular runtime

    //helpers and a version of regenerator-runtime.

    "@babel/runtime": "^7.0.0-beta.55",

    //babel comman line tool.

    "@babel/cli": "^7.2.3",

    "@babel/core": "^7.2.2",

    //a smart preset that allows you to use the latest JavaScript without needing to        //micromanage which syntax transforms

    "@babel/preset-env": "^7.3.1",

    //@babel/plugin-syntax-jsx

//@babel/plugin-transform-react-jsx

//@babel/plugin-transform-react-display-name

    //@babel/plugin-transform-react-jsx-self

//@babel/plugin-transform-react-jsx-source

    "@babel/preset-react": "^7.0.0",

    "babel-loader": "^8.0.5",

    "babel-plugin-transform-object-rest-spread": "^6.26.0",

    "css-loader": "^2.1.0",

    "html-loader": "^0.5.5",

    "style-loader": "^0.23.1",

    "html-webpack-plugin": "^4.0.0-beta.5",

    "clean-webpack-plugin": "^1.0.1",

    "webpack-cli": "^3.2.1",

    "webpack-dev-server": "^3.1.14"

  }

• 这里要注意的是@babel/polyfill，这个要放在dependencies里边，因为是polyfill,代码最后也是要在里边的，所以不能放在devDependencies里。接着看babel的配置文件。.babelrc

{

  "presets": [

    ["@babel/preset-env", {

      "targets": {

        "node": "current"

      }

    }],

    ["@babel/preset-react"]

  ],

  "plugins": [

    ["@babel/plugin-transform-runtime"],

    ["@babel/plugin-proposal-object-rest-spread",{ "useBuiltIns": true }]

  ]

}

• webpack.config.js

const path = require("path");

const webpack = require("webpack");

const HtmlWebpackPlugin = require('html-webpack-plugin');

const CleanWebpackPlugin = require('clean-webpack-plugin');

const baseConfig = {

  entry: [

    "@babel/polyfill", //这里要写，配置polyfill,也可以写在源码里

    "./src/index.js"

  ],

  devtool: 'cheap-module-source-map',//production的source map

  module: {

    rules: [

      {

        test: /\.css$/,

        use: [

          {

            loader:'style-loader'

          },

          {

            //这里注意，要使用css module以及css module的格式

            loader:'css-loader?modules&localIdentName=[name]_[hash:base64:5]',

          }

        ],

        exclude: /node_modules/,

      },

      {

        test: /\.(js|jsx)$/,

        exclude: /node_modules/,

        use: {

          //js/jsx使用babel-loader来处理 

          loader: 'babel-loader'

        }

      },

      {

        test: /\.html$/,

        use: [

          {

            loader: "html-loader"

          }

        ]

      }

    ]

  },

  plugins: [

    new CleanWebpackPlugin(['dist']),

    new HtmlWebpackPlugin({

      template: path.resolve(__dirname, 'src', 'index.html'),//模板

      filename: 'index.html',

      hash: true,//防止缓存

    }),

    new webpack.HotModuleReplacementPlugin()

  ],

  resolve: {

    extensions: ['*', '.js', '.jsx']

  },

  output: {

    publicPath: "",

    path: path.resolve(__dirname, "dist"),

    filename: "[name]-bundle.js"

  },

};

//增加这部分，当是开发环境的时候，再使用hmr和inline-source-map.

if (process.env.NODE_ENV === 'development') {

  baseConfig.devtool = 'inline-source-map';

  baseConfig.devServer = {

    contentBase: './dist',

    hot: true,

    open: true,

  };

}

module.exports = baseConfig;

• 然后写个简单的jsx

import React from 'react';

import * as style from '../css/main.css';

const HomeComponent = () => {

    //测试对象展开

    let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };

    console.log(x); // 1

    console.log(y); // 2

    console.log(z); // { a: 3, b: 4 }

    //测试array.from

    const arr = Array.from(new Set([1, 2, 3, 2, 1]));

    const arr2 = [1, [2, 3], [4, [5]]].flat(2);

    console.log(arr2);

    //测试下promise

    const promise = new Promise((resolve,reject)=>{

        console.log("promise");

        resolve(1);

    });

    //测试下symbol

    const sym = Symbol();

    console.log("symbol:"+sym.toString());

    return <div>

        <h2>Hello React16.7.0!</h2>

        <div className={style.hello}>Hello CSS Module!</div>

    </div>

};

export default HomeComponent;

到这里就能让react的一个最简单的例子跑起来了,看下index.js

import React from 'react';

import ReactDOM from 'react-dom';

import HomeComponent from './components/home'

ReactDOM.render(<HomeComponent />, document.getElementById('app'));

package.json里的scripts这样写

"scripts": {

    "prod": "webpack --mode production",

    "dev": "NODE_ENV=development webpack-dev-server --mode development --open"

  },