专题11: 将js/css打包进html，并配置 devServer

[技匠]

课题 2：搭建可插拔的开发环境跟生产环境

本章提要：

• 需要哪些包？
• 构建开发环境（devServer）
• 构建生产环境
• 自动生成 html
• 提取 css

需要哪些包？

package.json

{
  "scripts": {
    "dev": "cross-env NODE_ENV=development node build/dev.js",
    "build": "cross-env NODE_ENV=production node build/build.js"
  },
  "dependencies": {
    "@commitlint/config-conventional": "^8.2.0",
    "cross-env": "^6.0.3",
    "css-loader": "^3.2.0",
    "cssnano": "^4.1.10",
    "ora": "^4.0.3",
    "rimraf": "^3.0.0",
    "webpack": "^4.41.2"
  },
  "devDependencies": {
    "extract-text-webpack-plugin": "^3.0.2",
    "html-webpack-plugin": "^3.2.0",
    "mini-css-extract-plugin": "^0.8.0",
    "vue-cli-plugin-commitlint": "^1.0.4",
    "webpack-chain": "^6.0.0",
    "webpack-cli": "^3.3.10",
    "webpack-dev-server": "^3.9.0"
  }
}

目录

|-- build
  |-- base.js // 公共部分
  |-- build.js
  |-- dev.js
|-- config
  |-- base.js // 基础配置
  |-- css.js  // css 配置
  |-- HtmlWebpackPlugin.js // html 配置
  |-- MiniCssExtractPlugin.js // 提取css
|-- public  // 公共资源
  |-- index.html // html 模版
|-- src // 开发目录
  |-- style
  |---- index.css
  |-- main.js // 主入口

实现可插拔配置

build/base.js

const { findSync } = require('../lib');
const Config = require('webpack-chain');
const config = new Config();
const files = findSync('config');
const path = require('path');
const resolve = p => {
  return path.join(process.cwd(), p);
};

module.exports = () => {
  const map = new Map();

  files.map(_ => {
    const name = _.split('/')
      .pop()
      .replace('.js', '');
    return map.set(name, require(_)(config, resolve));
  });

  map.forEach((v, key) => {
    v();
  });

  return config;
};

生产环境搭建

build/build.js

const rimraf = require('rimraf');
const ora = require('ora');
const chalk = require('chalk');
const path = require('path');
// 删除 dist 目录
rimraf.sync(path.join(process.cwd(), 'dist'));

const config = require('./base')();
const webpack = require('webpack');
const spinner = ora('开始构建项目...');
spinner.start();

webpack(config.toConfig(), function(err, stats) {
  spinner.stop();
  if (err) throw err;
  process.stdout.write(
    stats.toString({
      colors: true,
      modules: false,
      children: false,
      chunks: false,
      chunkModules: false
    }) + '\n\n'
  );

  if (stats.hasErrors()) {
    console.log(chalk.red('构建失败\n'));
    process.exit(1);
  }

  console.log(chalk.cyan('build完成\n'));
});

开发环境搭建

build/dev.js

const config = require('./base')();
const webpack = require('webpack');
const chalk = require('chalk');
const WebpackDevServer = require('webpack-dev-server');
const port = 8080;
const publicPath = '/common/';

config.devServer
  .quiet(true)
  .hot(true)
  .https(false)
  .disableHostCheck(true)
  .publicPath(publicPath)
  .clientLogLevel('none');

const compiler = webpack(config.toConfig());
// 拿到 devServer 参数
const chainDevServer = compiler.options.devServer;
const server = new WebpackDevServer(
  compiler,
  Object.assign(chainDevServer, {})
);

['SIGINT', 'SIGTERM'].forEach(signal => {
  process.on(signal, () => {
    server.close(() => {
      process.exit(0);
    });
  });
});
// 监听端口
server.listen(port);

new Promise(() => {
  compiler.hooks.done.tap('dev', stats => {
    const empty = '    ';
    const common = `App running at:
    - Local: http://127.0.0.1:${port}${publicPath}\n`;
    console.log(chalk.cyan('\n' + empty + common));
  });
});

提取 css

config/css.js

module.exports = (config, resolve) => {
  return (lang, test) => {
    const baseRule = config.module.rule(lang).test(test);
    const normalRule = baseRule.oneOf('normal');
    applyLoaders(normalRule);
    function applyLoaders(rule) {
      rule
        .use('extract-css-loader')
        .loader(require('mini-css-extract-plugin').loader)
        .options({
          publicPath: './'
        });
      rule
        .use('css-loader')
        .loader('css-loader')
        .options({});
    }
  };
};

自动生成 html

config/HtmlWebpackPlugin.js

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

module.exports = (config, resolve) => {
  return () => {
    config.plugin('html').use(HtmlWebpackPlugin, [
      {
        template: 'public/index.html'
      }
    ]);
  };
};

css 提取插件

config/MiniCssExtractPlugin.js

const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = (config, resolve) => {
  return () => {
    config
      .oneOf('normal')
      .plugin('mini-css-extract')
      .use(MiniCssExtractPlugin);
  };
};

测试文件

测试 html 模板

public/index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>learn_webpack</title>
  <body></body>
</html>

测试 css 模板

src/style/index.css

.test {
  width: 200px;
  height: 200px;
  color: red;
  background-color: orange;
}

程序入口

src/main.js

require('./style/index.css');

const h2 = document.createElement('h2');
h2.className = 'test';
h2.innerText = 'test';
document.body.append(h2);

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