项目初始化$npminit安装webpack本次创建是基于webpack4$npminstall--save-dev新建webpack配置文件在根目
项目初始化
$ npm init安装webpack
本次创建是基于webpack4
$ npm install --save-dev新建webpack配置文件
在根目录创建build文件夹，添加一个js文件，命名为webpack.base.conf.js
// webpack.base.conf.js 文件
const path = require('path');
const DIST_PATH = path.resolve(__dirname, '../dist');
module.exports = {
entry: {
app: './app/index.js'
},
output: {
filename: "js/bundle.js",
path: DIST_PATH
}
};
使用merge的方式来组织webpack基础配置和不同环境的配置
先安装webpack-merge：
$ npm install --save-dev webpack-merge在build文件夹中再添加一个js文件，命名为 webpack.prod.conf.js
// webpack.prod.conf.js 文件
const merge = require('webpack-merge');
const baseWebpackConfig = require('./webpack.base.conf');
module.exports = merge(baseWebpackConfig, {
mode: 'production'
});
在根目录下创建app目录，然后创建index.js文件
var element =document.getElementById('root');
element.innerHTML = 'hello, world!';
在根目录创建一个public文件夹，然后新建一个index.html文件
// index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>从零开始搭建react工程</title>
</head>
<body>
<div id="root"></div>
<script src="../dist/js/bundle.js"></script>
</body>
</html>
当前项目目录树
|- /app
|- index.js
|- /node_modules
|- /public
|- index.html
|- /build
|- webpack.base.conf.js
|- webpack.prod.conf.js
|- package.json
|- package-lock.json
安装webpack-cli
webpack 4.0 版本之后的webpack，已经将webpack命令工具迁移到webpack-cli模块了,需要安装 webpack-cli
$ npm install --save-dev webpack-clipackage.json文件 scripts属性配置一个build命令
其值为：webpack --config build/webpack.prod.conf.js，以下是scripts的相关代码
// package.json
"scripts": {
"build": "webpack --config build/webpack.prod.conf.js",
"test": "echo \"Error: no test specified\" && exit 1"
},
安装React
$ npm install --save react react-dom修改app目录下的index.js的代码
import React from "react";
import ReactDom from "react-dom";
ReactDom.render(
<h1>hello, world!</h1>,
document.getElementById("root")
);
注意 import 属于ES6规范，因此需要转译ES2015+的语法，安装并配置 babel 以及相关依赖
$ npm install --save-dev babel-loader babel-core babel-preset-env babel-preset-react
根目录创建.babelrc文件，配置presets.
{
"presets": [
[
"env",
{
"targets": {
"browsers": [
"> 1%",
"last 5 versions",
"ie >= 8"
]
}
}
],
"react"
]
}
修改webpack.base.conf.js文件
// webpack.base.conf.js
const path = require('path');
const APP_PATH = path.resolve(__dirname, '../app');
const DIST_PATH = path.resolve(__dirname, '../dist');
module.exports = {
entry: {
app: './app/index.js'
},
output: {
filename: 'js/bundle.js',
path: DIST_PATH
},
module: {
rules: [
{
test: /\.js?$/,
use: "babel-loader",
include: APP_PATH
}
]
}
};
运行 npm run build
添加插件
public下的index.html本该自动添加到dist目录，并且引用资源自动加载到该文件，通过html-webpack-plugin实现这一步
$ npm install html-webpack-plugin --save-devwebpack.prod.conf.js中配置plugins属性
const merge = require('webpack-merge');
const baseWebpackConfig = require('./webpack.base.conf.js');
const HtmlWebpackPlugin = require('html-webpack-plugin');
module.exports = merge(baseWebpackConfig, {
mode: 'production',
plugins: [
new HtmlWebpackPlugin({
template: 'public/index.html',
inject: 'body',
minify: {
removeComments: true,
collapseWhitespace: true,
removeAttributeQuotes: true
},
})
]
});
删除 index.html 中手动引入的 script 标签
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>从零开始搭建react工程</title>
</head>
<body>
<div id="root"></div>
</body>
</html>
重新编译查看 npm run build 浏览器打开查看目录 dist 下的 index.html
以上步骤都成功的前提下继续走下一步
生成的文件名添加Hash值，目的是解决缓存问题
修改webpack.prod.conf.js，mode: 'production', 增加以下代码
// webpack.prod.conf.js
output: {
filename: "js/[name].[chunkhash:16].js",
},
生成前需要清理之前项目生成的文件，因为由于文件名的改变如果不删除会一直增加
安装插件 clean-webpack-plugin
$ npm install --save-dev clean-webpack-plugin
修改 webpack.prod.conf.js
// webpack.prod.conf.js
const merge = require('webpack-merge');
const baseWebpackConfig = require('./webpack.base.conf.js');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');
module.exports = merge(baseWebpackConfig, {
mode: 'production',
output: {
filename: "js/[name].[chunkhash:16].js",
},
plugins: [
new HtmlWebpackPlugin({
template: 'public/index.html',
inject: 'body',
minify: {
removeComments: true,
collapseWhitespace: true,
removeAttributeQuotes: true
},
}),
new CleanWebpackPlugin(['../dist'], { allowExternal: true })
]
});
公共代码与业务代码分离
修改 webpack.base.conf.js 的 entry 入口属性，抽出框架代码
entry: {
app: './app/index.js',
framework: ['react','react-dom'],
},修改webpack.prod.conf.js，增加以下代码，目的是分离框架代码和业务代码
虽然上面步骤抽出框架代码生成两个文件，但是app.js还是包含框架代码
optimization: {
splitChunks: {
chunks: "all",
minChunks: 1,
minSize: 0,
cacheGroups: {
framework: {
test: "framework",
name: "framework",
enforce: true
}
}
}
}
cacheGroups对象，定义了需要被抽离的模块
其中test属性是比较关键的一个值，他可以是一个字符串，也可以是正则表达式，还可以是函数。如果定义的是字符串，会匹配入口模块名称，会从其他模块中把包含这个模块的抽离出来
name是抽离后生成的名字，和入口文件模块名称相同，这样抽离出来的新生成的framework模块会覆盖被抽离的framework模块
整合 webpack-dev-server
开发环境开启服务监听文件改动实时更新最新内容
$ npm install --save-dev webpack-dev-server
在build中添加webpack.dev.conf.js文件
const path = require('path');
const merge = require('webpack-merge');
const baseWebpackConfig = require('./webpack.base.conf.js');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const webpack = require('webpack');
module.exports = merge(baseWebpackConfig, {
mode: 'development',
output: {
filename: "js/[name].[hash:16].js",
},
plugins: [
new HtmlWebpackPlugin({
template: 'public/index.html',
inject: 'body',
minify: {
html5: true
},
hash: false
}),
new webpack.HotModuleReplacementPlugin()
],
devServer: {
port: '8080',
contentBase: path.join(__dirname, '../public'),
compress: true,
historyApiFallback: true,
hot: true,
https: false,
noInfo: true,
open: true,
proxy: {}
}
});
在package.json scripts属性添加内容
"dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",npm run dev
自动打开浏览器打开入口页面实时更新
独立导出 css 文件
安装css相关依赖
sass less 预处理
$ npm install extract-text-webpack-plugin
$ npm install style-loader css-loader postcss-loader autoprefixer --save-dev
$ npm install less sass less-loader sass-loader stylus-loader node-sass --save-dev
webpack.base.conf.js 文件修改
// webpack.base.conf.js
{
test: /\.css$/,
use: [
{
loader: "style-loader" //在html中插入<style>标签
},
{
loader: "css-loader",//获取引用资源，如@import,url()
},
{
loader: "postcss-loader",
options: {
plugins:[
require('autoprefixer')({
browsers:['last 5 version']
})
]
}
}
]
},
{
test:/\.less$/,
use: [
{ loader: "style-loader" },
{ loader: "css-loader" },
{
loader: "postcss-loader",//自动加前缀
options: {
plugins:[
require('autoprefixer')({
browsers:['last 5 version']
})
]
}
},
{ loader: "less-loader" }
]
},
{
test:/\.scss$/,
use:[
{ loader: "style-loader" },
{
loader: "css-loader",
},
{ loader: "sass-loader" },
{
loader: "postcss-loader",
options: {
plugins:[
require('autoprefixer')({
browsers:['last 5 version']
})
]
}
}
]
},图片和路径处理
$ npm i file-loader url-loader --save-devwebpack.base.conf.js 文件修改
// webpack.base.conf.js
{
test: /\.(png|jpg|gif|woff|svg|eot|woff2|tff)$/,
use: 'url-loader?limit=8129',
//注意后面那个limit的参数，当你图片大小小于这个限制的时候，会自动启用base64编码图片
exclude: /node_modules/
}
build 时报错
Error: Chunk.entrypoints: Use Chunks.groupsIterable and filter by instanceof Entrypoint instead at Chunk.get (F:\react\createApp\node_modules\webpack\lib\Chunk.js:824:9)
webpack4.0中使用“extract-text-webpack-plugin”报错
解决办法
$ npm install extract-text-webpack-plugin@next背景图片路径问题
由于css文件分离出来的原因，会导致在css文件夹下找images文件夹下的图片
解决办法 publicPath属性改为 '/'，以绝对路径的方式寻找资源
{
test:/\.(png|jpg|gif)$/,
use:[{
loader:'url-loader',
options: {
// outputPath:'../',//输出**文件夹
publicPath: '/',
name: "images/[name].[ext]",
limit:500 //是把小于500B的文件打成Base64的格式，写入JS
}
}]
},
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
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