Detailed explanation on the use of babel-loader file preprocessor-JS Tutorial-php.cn

Detailed explanation on the use of babel-loader file preprocessor

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Release： 2018-03-26 09:01:37

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The official explanation of loader is a file preprocessor. In layman's terms, when webpack processes static files, it needs to use loader to load various files, such as: html files need to use html-loader, css needs to use css-loader, style-loader and so on. Today we are introduced to babel-loader, which is used to process ES6 syntax and compile it into js syntax that the browser can execute.

Installation

We need to use babel-loader babel-core babel-preset

Compatible version: webpack 3. x | babel-loader 8.x | babel 7.x

npm install babel-loader@8.0.0-beta.0 @babel/core @babel/preset-env webpack
webpack 3.x babel-loader 7.x | babel 6.x

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Use

Let’s start with a little chestnut:

var htmlWebpackPlugin = require(&#39;html-webpack-plugin&#39;)

const path = require(&#39;path&#39;)
module.exports = {
  mode: &#39;development&#39;,
  entry: &#39;./src/app.js&#39;,
  output: {
    filename: &#39;js/bundle.js&#39;,
    path: path.resolve(__dirname, &#39;dist&#39;)
  },
  module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /(node_modules|bower_components)/, // (不处理node_modules 和 bower_components下的js文件) 优化处理加快速度
        use: {
          loader: &#39;babel-loader&#39;,
          options: {     // options选项中的presets设置的就是当前js的版本
            presets: [&#39;@babel/preset-env&#39;]
          }
        }
      }
    ]
  },
  plugins: [
    new htmlWebpackPlugin({
      template: &#39;index.html&#39;,
      inject: &#39;body&#39;,
      filename: &#39;index.html&#39;
    })
  ]
}

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You can use the options attribute to pass options to the loader.

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