从零开始学VUE之Webpack(使用BabelLoader实现ES6语法打包转ES5语法)

npm install --save-dev babel-loader@7 babel-core babel-preset-es2015

D:\zhangyugen@jd.com\vue\day1\html\4.从0开始学VUE\simpleloader>npm install --save-dev babel-loader@7 babel-core babel-preset-es2015
npm WARN deprecated babel-preset-es2015@6.24.1: ?  Thanks for using Babel: we recommend using babel-preset-env now: please read https://babeljs.io/env to update!
npm WARN deprecated core-js@2.6.12: core-js@<3.3 is no longer maintained and not recommended for usage due to the number of issues. Because of the V8 engine whims, feature detection in old core-js versions could cause a slowdown up to 100x even if nothing is polyfilled. Please, upgrade your dependencies to the actual version of core-js.

> core-js@2.6.12 postinstall D:\zhangyugen@jd.com\vue\day1\html\4.从0开始学VUE\simpleloader\node_modules\core-js
> node -e "try{require('./postinstall')}catch(e){}"

Thank you for using core-js ( https://github.com/zloirock/core-js ) for polyfilling JavaScript standard library!

The project needs your help! Please consider supporting of core-js on Open Collective or Patreon:
> https://opencollective.com/core-js
> https://www.patreon.com/zloirock

Also, the author of core-js ( https://github.com/zloirock ) is looking for a good job -)

npm WARN css-loader@3.6.0 requires a peer of webpack@^4.0.0 || ^5.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN style-loader@2.0.0 requires a peer of webpack@^4.0.0 || ^5.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN simpleconfig@1.0.0 No description
npm WARN simpleconfig@1.0.0 No repository field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@2.3.2 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@2.3.2: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.13 (node_modules\watchpack-chokidar2\node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

+ babel-loader@7.1.5
+ babel-preset-es2015@6.24.1
+ babel-core@6.26.3
added 85 packages from 15 contributors and audited 491 packages in 53.006s

13 packages are looking for funding
  run `npm fund` for details

found 10 vulnerabilities (2 low, 8 moderate)
  run `npm audit fix` to fix them, or `npm audit` for details

D:\zhangyugen@jd.com\vue\day1\html\4.从0开始学VUE\simpleloader>

// 需要从node依赖中引入 需要添加依赖环境
const path = require('path');

module.exports = {
    // 配置源码打包位置
    entry: './src/main.js',
    // 配置目标位置
    output: {
        // path 只能写绝对路径 不能写相对路径 但是不要直接写死,需要动态获取文件位置
        path: path.resolve(__dirname,'dist'),
        filename: 'bundle.js'
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [ 'style-loader', 'css-loader' ]
            },
          // 增加转换配置
            {
                test: /\.js$/,
                exclude: /(node_modules|bower_components)/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        presets: ['es2015']
                    }
                }
            }
        ]
    }
}