Webpack learning summary

This is the 7th day of my participation in Gwen Challenge

start

The NPM init initialization project is executed
Create a new SRC folder to store the project code
Create a build folder to store the packaged output files of the project

Type in index1.js

import person from './person.json'

console.log(person)

function add(x, y) {
	return x + y
}
console.log(add(2.3))
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Webpack. / SRC /index -o./build/build.js –mode=development
Package./ SRC /index.js output into./build/index.js
To simplify things, you can write this command to the package.json configuration file and give it an alias
Add: “build”: “webpack. / SRC /index.js -o./build/build.js –mode=development” to the script property

You can then execute NPM run build instead to achieve the same effect

Package information includes file size, time, and hash value

Packaging CSS

Create webpack.config.js, the webpack configuration file

const path = require('path')
module.exports = {
	entry: './src/index.js'.// Import file
	output: { // Output file
		filename: 'build.js'.// The output file name
		path: path.resolve(__dirname, 'build') // The path to the output file
	},
	module: { // The dependent module
		rules: [{
				test: /\.css$/.// Matches a file with the suffix CSS
				use: [// Write in the correct order
					'style-loader'.// Insert the js style string into the HTML page as a head tag
					'css-loader'.// Change the styles in the CSS file to js strings]},]},plugins: [].mode: 'development',}Copy the code

Creating a CSS File

// Write a simple stylehtml.body {
	margin: 0;

}

body {
	background-color: aqua;
}
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Import ‘./index.css’ from the entry file index.js to introduce index.css
After repackaging, you can see that index.css has been introduced in build.js
Open the index.html file and see the imported styles inside

Packaging HTML

Download the html-webpack-plugin
Const HtmlWebpackPlugin = require(‘html-webpack-plugin’)

Add configuration in webpakc.config.js

	plugins: [
		new HtmlWebpackPlugin({
			title: 'Output Management'// Title title of the HTML file
			template: './src/index.html',// Customize the template file})].Copy the code

May be an Error: Error: always find module ‘webpack/lib/node/NodeTemplatePlugin’

NPM install webpack –save-dev re-install webpack in current project (global install may not find)

Packaging pictures

file-loader

Download file-loader NPM install file-loader -d

Add configuration to Module

{
    test: /\.(jpg|jpg|gif)$/,// Matches files with these suffixes
    use: [{
        loader: 'file-loader',
        options: {// File loader configuration option}}}]Copy the code

url-loader

Url-loader is similar to file-loader except that it can limit file size

Download NPM install url-loader -d

Add configuration to Module

    rules: [
      {
        test: /\.(png|jpg|gif)$/,
        use: [
          {
            loader: 'url-loader'.options: {
              limit: 8192// If the file size is less than 8192 bytes, it is imported as base64, otherwise it is imported normally (path form)}}]}]Copy the code

devServer

Files can be automatically packaged when they are changed, avoiding repeated packaging and improving development efficiency

Download the plugin NPM install webpack-dev-server -d

Add a devServer property to save the configuration

DevServer: {contentBase: path.resolve(__dirname, 'build'), True,// Whether the browser automatically opens}Copy the code

Extracting CSS files

The style-loader dependency is to insert CSS into the HEAD tag of an HTML file, imported internally
NPM install mini-css-extract-plugin-d

Add the configuration to the plugins property

//const MiniCssExtractPlugin = require('mini-css-extract-plugin'
new MiniCssExtractPlugin({
    filename: 'css/build.css'
})
		
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Change the CSS loading mode in the module

{
    test: /\.css$/,
    use: [
    // 'style-loader',// generate a style tag and place it in the style
    MiniCssExtractPlugin.loader,// Link label is imported externally
    'css-loader',
    ]
}
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CSS compression

NPM install optimize- CSS-assets -webpack-plugin -d

Configure in plugins

/ / const OptimizeCssAssetsWebpackPlugin = the require (' optimize - CSS - assets - webpack - plugin ') / / introduction in advance
new OptimizeCssAssetsWebpackPlugin()
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Js syntax check

NPM install eslint eslint-loader -d the eslint-loader used depends on ESlint
Using the Airbnb specification, download an eslin-config-Airbnb-base package, NPM instal eslint-config-base eslint-plugin-import -d instal eslint-config-base eslint-plugin-import -d

Add verification rules to module

{
    test: /\.js$/.// Matches the js file
    exclude: /node_modules/.// Exclude the contents of the node_modules folder without validation
    loader: 'eslint-loader'./ / rely on
    options: {}/ / configuration items
}
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Add an additional property —-**eslintConfig ** to package.json
```
"EslintConfig ":{"extends":"airbnb-base"}Copy the code
```
Package files to see a bunch of errors, and then follow the prompts to change the errors a little bit

Js compatibility processing

babel-loader

Download NPM install babel-loader @babel/preset-env -d

Configure rules in module

{
    test: /\.js$/,
    exclude: /node_modules/,
    loader: 'babel-loader',
    options: {
        presets: [
        '@babel/preset-env'
        ]
    }
}
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Add ES6 syntax to js files
After packaging, you can see the packaged file with a syntax change from const to var

@babel/ Polyfill all compatible

downloadnpm install @babel/polyfill - D
Directly at the top of the JS file import '@babel/polyfill'
The packed file is too large

Core.js is compatible with loading on demand

Download NPM install core.js -d

Add configuration to Module

{
    test: /\.js$/,// Matches the js file
    exclude: /node_modules/,// Exclude files in node_modules
    loader: 'babel-loader',/ / rely on
    options: {/ / configuration items
        presets: [
            [
                '@babel/preset-env',
                {
                    useBuiltIns: 'usage',// Load as needed
                    corejs: {
                        version: 3/ / core. Js version
                    },
                    targets: {
                        chrome: '60',// Compatible with Chrome to version 60
                        firefox: '60',
                        ie: '9',
                        safari: '10',
                        edge: '17',}}]]}},Copy the code

Pay attention to the point

Babel-loader is only compatible with simple syntax, but not with complex syntax such as Promise
@babel/ Polyfill is simple to use but too big to pack
It is recommended to use core.js to load compatibility on demand

Clear the last packed file

Download the plugin npm install clen-webpack-plugin -D
The introduction of the pluginconst {CleanWebpackPlugin} = require('clean-webpack-plugin')
Plugin configuration in webpack.config.js

	new CleanWebpackPlugin()
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Matches the precedence of the suffix name

resolve:{
	extensions: ['.js'.'.vue'.'.json'].// "extensions"
}
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Complete configuration file

const path = require('path')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const MiniCssExtractPlugin = require('mini-css-extract-plugin')
const OptimizeCssAssetsWebpackPlugin = require('optimize-css-assets-webpack-plugin')
module.exports = {
	entry: './src/index.js'.output: {
		filename: 'js/build.js'.path: path.resolve(__dirname, 'build')},module: {
		rules: [{
				test: /\.css$/,
				use: [
					MiniCssExtractPlugin.loader,
					'css-loader',]}, {test: /\.(jpg|png|gif)$/,
				loader: 'file-loader',},/ / {
			// test: /\.js$/,
			// exclude: /node_modules/,
			// loader: 'babel-loader',
			// options: {
			// presets: [
			/ / /
			// '@babel/preset-env',
			/ / {
			// useBuiltIns: 'usage',
			// corejs: {
			// version: 3
			/ /},
			// targets: {
			// chrome: '60',
			// firefox: '60',
			// ie: '9',
			// safari: '10',
			// edge: '17',
			/ /}
			/ /}
			/ /]
			/ /]
			/ /}
			// },
			/ / {
			// test: /\.js$/,
			// exclude: /node_modules/,
			// loader: 'eslint-loader',
			// options: {}
			// }]},plugins: [
		new HtmlWebpackPlugin({
			template: './src/index.html'.minify: {collapseWhitespace:true.removeComments:true,}}),new MiniCssExtractPlugin({
			filename: 'css/index.css',}).new OptimizeCssAssetsWebpackPlugin({

		})
	],
	mode: "production".devServer: {
		hot:true.port: 3000.open: true.compress: true.// Whether to compress files
		contentBase: path.resolve(__dirname, 'build')}}Copy the code

start

Packaging CSS

Packaging HTML

Packaging pictures

file-loader

url-loader

devServer

Extracting CSS files

CSS compression

Js syntax check

Js compatibility processing

babel-loader

@babel/ Polyfill all compatible

Core.js is compatible with loading on demand

Pay attention to the point

Clear the last packed file

Matches the precedence of the suffix name

Complete configuration file

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