Webpack quick start tutorial

1. Introduction to WebPack

Learn about Webpack

What is a webpackzz
- Webpack is a module bundler.
- In Webpack’s view, all the front-end resource files (js/json/ CSS /img/less/…) Will be handled as modules
- It performs static analysis based on the dependencies of modules and generates corresponding static resources
Understand the Loader
- Webpack itself can only load JS/JSON modules. If you want to load other types of files (modules), you need to use the corresponding loader for conversion/loading
- Loader itself is also a JavaScript module running in the Node.js environment
- It is itself a function that takes the source file as an argument and returns the result of the transformation
- Loaders are usually named in the format of xxX-loader. XXX represents the conversion functions to be performed by the loader, such as jSON-loader.
Configuration file (default)
- Webpack.config. js: is a Node module that returns a configuration information object in JSON format
The plug-in
- Plug-ins can perform some functions that cannot be performed by loaders.
- The use of plug-ins is typically specified in the Plugins option of the WebPack configuration information.
- CleanWebpackPlugin: Automatically cleans up specified folder resources
- HtmlWebpackPlugin: Automatically generates HTML files and
- UglifyJSPlugin: compresses JS files

2. Learning documents:

Webpack: webpack.github. IO /
Webpack2 document (English): webpack.js.org/
Webpack2 document (Chinese): doc.webpack-china.org/

3. Start the project

Initialize the project:

Generate a package.json file

{"name": "webpack_test", "version": "1.0.0"}Copy the code

Install webpack

NPM install webpack -g // Global install

-npm install webpack --save-dev // Local installCopy the code

4. Compile and package your app

Create the entry SRC /js/ : entry.js

document.write(“entry.js is work”);

Create the main page: dist/index.html

<script type="text/javascript" src="bundle.js"></script>
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Compile the js
- webpack src/js/entry.js dist/bundle.js
View the page effect

Add js/ JSON file

Create a second js: SRC /js/math.js

export function square(x) {
  return x * x;
}

export function cube(x) {
  return x * x * x;
}
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Create a JSON file: SRC /json/data.json

{
  "name": "Tom",
  "age": 12
}
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Update the entry js: entry.js

import {cube} from './math' import data from '.. // Note that data is automatically converted to a native JS object or array document.write("entry.js is work <br/>"); document.write(cube(2) + '<br/>'); document.write(JSON.stringify(data) + '<br/>')Copy the code

Compile the js:

webpack src/js/entry.js dist/bundle.js
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View the page effect

6. Use webpack profiles

Create a webpack. Config. Js

const path = require('path'); // Path is a built-in module for setting the path. Module. exports = {entry: './ SRC /js/entry.js', // exports = {entry: './ SRC /js/entry.js', // exports = {entry: '. Path.resolve (__dirname, 'dist') // Output file path configuration}};Copy the code

Configure the NPM command: package.json

"scripts": {
  "build": "webpack"
},
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Packaging application
```
npm run build
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```

7. Package CSS and image files

Install style loader

NPM install csS-loader style-loader --save-dev NPM install file-loader URl-loader --save-dev Url-loader is the upper-layer encapsulation of the file-loader object and must be used together with the file-loader.Copy the code

Configure the loader

module: {
  rules: [
    {
      test: /.css$/,
      use: [
        'style-loader',
        'css-loader'
      ]
    },
    {
      test: /.(png|jpg|gif)$/,
      use: [
        {
          loader: 'url-loader',
          options: {
            limit: 8192      
          }
        }
      ]
    }
  ]
}
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Add 2 images to the app:
- Inset: img/logo. PNG
- Big PIC: img/big. JPG

Create a style file: SRC/CSS /test.css

body { background: url('.. /img/logo.jpg') }Copy the code

Update the entry js: entry.js
- import ‘.. /css/test.css’

Adding CSS Styles

#box1{ width: 300px; height: 300px; background-image: url(".. /image/logo.jpg"); } #box2{ width: 300px; height: 300px; background-image: url(".. /image/big.jpg"); }Copy the code

Index.html to add elements

  <div id="box1"></div>
  <div id="box2"></div>
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Execute the package command:
```
npm run build
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```
Identify problems:
- Large images cannot be packaged into the entry.js file, and index.html is not in the build resources directory.
- The images loaded on the page will be searched in the directory where they are located. As a result, the large image path cannot be found when the images are loaded on the page
- The solution:
- Use publicPath: ‘dist/js/’ // to set the path for the resources in index.html. All resources will be found in the current directory.
- Putting index.html in dist/js/ also works.

8. Automatic compilation and packaging

Use the WebPack development server tool: webpack-dev-server
download
- npm install –save-dev webpack-dev-server

Webpack configuration

 devServer: {
   contentBase: './dist'
 },
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Package configuration
- “start”: “webpack-dev-server –open”
Compile the packaged application and run it
- npm start

9. Use webPack plug-ins

Common plug-ins
- Use the HTml-webpack-plugin to generate pages that import script from the template HTML
- Clean up the dist folder using the clean-webpack-plugin
- Use uglifyjs-webpack-plugin to compress the packaged JS file

download

npm install --save-dev  html-webpack-plugin clean-webpack-plugin
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Webpack configuration

const HtmlWebpackPlugin = require('html-webpack-plugin'); // Plugin that automatically generates HTML files const CleanWebpackPlugin = require('clean-webpack-plugin'); [new HtmlWebpackPlugin({template: './index.html'}), new CleanWebpackPlugin(['dist']),]Copy the code

Create the page: index.html

<! DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>webpack test</title> </head> <body> <div id="app"></div> <! </body> </ HTML >Copy the code

Package the project
```
npm run build
npm start
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```

2. Configure the webpack.config.js file.

const path = require('path'); const HtmlWebpackPlugin = require('html-webpack-plugin'); // Plugin that automatically generates HTML files const CleanWebpackPlugin = require('clean-webpack-plugin'); Module. exports = {entry: './ SRC /js/entry.js', output: {filename: 'bundle.js', // publicPath: 'dist/js/', path: path.resolve(__dirname, 'dist/js') }, module: { rules: [ { test: /.css$/, use: [ 'style-loader', 'css-loader' ] }, { test: /.(png|jpg|gif)$/, use: [ { loader: 'url-loader', options: { limit: 8192 } } ] } ] }, plugins: [ new HtmlWebpackPlugin({template: './index.html'}), new CleanWebpackPlugin(['dist']), ] };Copy the code

Learn about Webpack

2. Learning documents:

3. Start the project

4. Compile and package your app

Add js/ JSON file

6. Use webpack profiles

7. Package CSS and image files

8. Automatic compilation and packaging

9. Use webPack plug-ins

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