*安装webpack-dev-server包

npm i webpack-dev-server
# 在不同平台上设置环境变量的方式不同，用cross-env统一设置环境变量
npm i cross-env

• 在package.json文件中，增加“dev”命令；

{
  "name": "webpack-practice",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "cross-env NODE_ENV=production webpack --config webpack.config.js",
    "dev": "cross-env NODE_ENV=development webpack-dev-server --config webpack.config.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "cross-env": "^5.2.0",
    "css-loader": "^0.28.11",
    "file-loader": "^1.1.11",
    "style-loader": "^0.21.0",
    "stylus": "^0.54.5",
    "stylus-loader": "^3.0.2",
    "url-loader": "^1.0.1",
    "vue": "^2.5.16",
    "vue-loader": "^13.7.2",
    "vue-template-compiler": "^2.5.16",
    "webpack": "^3.12.0",
    "webpack-dev-server": "^2.9.1"
  }
}

• 在webpack.config.js文件中全局增加target：‘web’并判断当前运行模式是webpack还是webpack-dev-server

const path = require('path')

// 由于不同模式，使用的是同一个webpack.config.js
// 设置一个变量，判断是否为dev开发模式
const isDev = process.env.NODE_ENV === 'development'

const config = {
    target: 'web',
    entry: path.join(__dirname, 'src/index.js'),
    output: {
        filename: 'bundle.js',
        path:path.join(__dirname, 'dist')
    },
    module: {
        rules: [
            {
                test: /\.vue$/,
                loader: 'vue-loader'
            },
            {       
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader'
                ]
            },
            {
                test: /\.styl/,
                use: [
                    'style-loader',
                    'css-loader',
                    'stylus-loader'
                ]
            },
            {
                test: /\.(gif|jpg|jpeg|png|svg)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            limit: 1024,
                            name: '[name].[ext]'
                        }
                    }
                ]
            }
        ]
    }
}

if (isDev) {
    config.devServer = {
        port: 8000,
        host: '0.0.0.0',
        overlay: {
            errors: true  // webpack编译过程中有任何错误都会提示在页面上
        }
    }
}

module.exports = config

• 整个项目要需要一个HTML文件作为入口

npm i html-webpack-plugin

使用该插件

const path = require('path')
const HTMLPlugin = require('html-webpack-plugin')
const webpack = require('webpack')

// 判断是否为dev开发模式
const isDev = process.env.NODE_ENV === 'development'

const config = {
    target: 'web',
    entry: path.join(__dirname, 'src/index.js'),
    output: {
        filename: 'bundle.js',
        path:path.join(__dirname, 'dist')
    },
    module: {
        rules: [
            {
                test: /\.vue$/,
                loader: 'vue-loader'
            },
            {       
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader'
                ]
            },
            {
                test: /\.styl/,
                use: [
                    'style-loader',
                    'css-loader',
                    'stylus-loader'
                ]
            },
            {
                test: /\.(gif|jpg|jpeg|png|svg)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            limit: 1024,
                            name: '[name].[ext]'
                        }
                    }
                ]
            }
        ]
    },
    plugins: [
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: isDev ? '"development"' : '"production"'
            }
        }),
        new HTMLPlugin()
    ]
}

if (isDev) {
    config.devServer = {
        port: 8000,
        host: '0.0.0.0',
        overlay: {
            errors: true
        }
    }
}

module.exports = config

• 热加载配置

const path = require('path')
const HTMLPlugin = require('html-webpack-plugin')
const webpack = require('webpack')

// 判断是否为dev开发模式
const isDev = process.env.NODE_ENV === 'development'

const config = {
    target: 'web',
    entry: path.join(__dirname, 'src/index.js'),
    output: {
        filename: 'bundle.js',
        path:path.join(__dirname, 'dist')
    },
    module: {
        rules: [
            {
                test: /\.vue$/,
                loader: 'vue-loader'
            },
            {       
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader'
                ]
            },
            {
                test: /\.styl/,
                use: [
                    'style-loader',
                    'css-loader',
                    'stylus-loader'
                ]
            },
            {
                test: /\.(gif|jpg|jpeg|png|svg)$/,
                use: [
                    {
                        loader: 'url-loader',
                        options: {
                            limit: 1024,
                            name: '[name].[ext]'
                        }
                    }
                ]
            }
        ]
    },
    plugins: [
        new webpack.DefinePlugin({
            'process.env': {
                NODE_ENV: isDev ? '"development"' : '"production"'
            }
        }),
        new HTMLPlugin()
    ]
}

if (isDev) {
    // 方便在浏览器看见编译之前的代码，而非编译之后的
    config.devtool = '#cheap-module-eval-source-map'
    config.devServer = {
        port: 8000,
        host: '0.0.0.0',
        overlay: {
            errors: true
        },
        hot: true
    },
    config.plugins.push(
        // 热加载
        new webpack.HotModuleReplacementPlugin(),
        // 处理报错信息
        new webpack.NoEmitOnErrorsPlugin()
    )
}

module.exports = config