学习webpack

#第一节
=======
webpack安装4.6.0
npm install -g webpack
npm install webpack-cli -g
webpack -v

npm init创建项目
npm install
npm install --save-dev webpack

卸载: npm uninstall webpack -g
npm install webpack-cli --save-dev

#第二节
=======
webpack打包
webpack src/b.js --output-filename a.js
会把src下的b.js打包到dist/a.js

#第三节
=======
配置webpack.config.js
配置入口和出口
const path=require('path');

module.exports={
entry:{//入口
entry:'./src/b.js',
entry2:'./src/b2.js'
},
output:{//出口
path:path.resolve(__dirname,'dist'),
filename:'[name].js'
},
module:{},
plugins:[],
devServer:{}
}
命令行输入webpack打包文件

#第四节
=======
热更新和服务
配置webpack.config.js
devServer:{
contentBase:path.resolve(__dirname,'dist'),//文件路径要监听的文件
host:'192.168.1.168',//本机ip地址 ipconfig查看本机ip
compress:true,//是否启用服务器压缩
port:1717 //端口号
}
npm install webpack-dev-server --save-dev

#第五节
=======
打包css文件
在js中引入css import css from './css/index.css';
安装
npm install style-loader --save-dev
npm install css-loader --save-dev
配置webpack.config.js

module:{
rules:[
{
test:/\.css$/,
use: ["style-loader", "css-loader"]
}
]
},
或者
module:{
rules:[
{
test:/\.css$/,
use:[{
loader:"style-loader"
},{
loader:"css-loader"
}]
}
]
},

#第六节
=======
js压缩
配置webpack.config.js
引入
const uglify = require('uglifyjs-webpack-plugin');

plugins:[
new uglify()
],

#第七节
=======
html文件打包
cnpm install --save-dev html-webpack-plugin
引入
配置webpack.config.js
const htmlPlugin=require('html-webpack-plugin');

plugins:[
// new uglify()
new htmlPlugin({
minify:{
removeAttributeQuotes:true
},
hash:true,
template:'./src/index.html'
})
],
#第八节
=======
css引入图片
图片写成背景
安装
npm install --save-dev file-loader url-loader
配置webpack.config.js
rules:[
{
test:/\.css$/,
use:[{
loader:"style-loader"
},{
loader:"css-loader"
}]
},{
test:/\.(png|jpg|gif)/,
use[{
loader:'url-loader',
options:{
limit:50000
}
}]
}
]
#第九节
=======
css分离
安装
npm install --save-dev extract-text-webpack-plugin
如果出现错误
Error: Chunk.entrypoints: Use Chunks.groupsIterable and filter by instanceof Entrypoint instead

npm install extract-text-webpack-plugin@next
配置
webpack.config.js
引入
const extractTextPlugin=require('extract-text-webpack-plugin');
rules:[
{
test:/\.css$/,
use:extractTextPlugin.extract({
fallback: "style-loader",
use: "css-loader"
})
},{
test:/\.(png|jpg|gif)/,
use:[{
loader:'url-loader',
options:{
limit:500
}
}]
}
]
new extractTextPlugin("/css/index.css"),
处理图片路径
var website={
publicPath:'http://192.168.1.168:1717/'
}
output:{//出口
path:path.resolve(__dirname,'dist'),
filename:'[name].js',
publicPath:website.publicPath
},

#第十节
=======

图片打包到images文件夹下
配置
webpack.config.js
rules:[
{
test:/\.css$/,
use:extractTextPlugin.extract({
fallback: "style-loader",
use: "css-loader"
})
},{
test:/\.(png|jpg|gif)/,
use:[{
loader:'url-loader',
options:{
limit:500,
outputPath:'images/'
}
}]
}
]
局部安装webpack
运行webpack
配置
package.json
"scripts": {
"server": "webpack-dev-server",
"build":"webpack"
},

处理html中img引入图片
安装国人写的
cnpm insatll --save-dev html-withimg-loader
配置
webpack.config.js
rules:[
{
test:/\.css$/,
use:extractTextPlugin.extract({
fallback: "style-loader",
use: "css-loader"
})
},{
test:/\.(png|jpg|gif)/,
use:[{
loader:'url-loader',
options:{
limit:500,
outputPath:'images/'
}
}]
},
{
test:/\.(html|htm)$/,
use:[ 'html-withimg-loader']
}
]