首先npm inIT一路回车 新建webpack.dev.config.js，修改package.json文件，安装webpack-dev-server可以帮助你在代码发生变化后自动编译代码

修改package.json文件

 "scripts": {
    "dev": "webpack-dev-server --config ./webpack.dev.config.js --mode development"
  },

webpack.dev.config.js

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

module.exports = {
    entry: './src/index.js',
    output: {
        path: __dirname,
        filename: './release/bundle.js'  // release 会自动创建
    },
    plugins: [
        new HtmlWebpackPlugin({
            template: './index.html'  // bundle.js 会自动注入
        })
    ],
    devServer: {
        contentBase: path.join(__dirname, "./release"),  // 根目录
        oPEn: true,  // 自动打开浏览器
        port: 9000,   // 端口
        Proxy: {
            '/api/*': {
                target: 'http://localhost:8880'
            }
        }
    },
    module: {
        rules: [{
            test: /.js?$/,
            exclude: /(node_modules)/,
            loader: 'babel-loader'
        }]
    }
}

package.JSON 依据上面的方式，安装以下依赖

{
  "name": "es6",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "dev": "webpack-dev-server --config ./webpack.dev.config.js --mode development"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-core": "^6.26.3",
    "babel-loader": "^7.1.4",
    "babel-plugin-transform-decorators-legacy": "^1.3.4",
    "babel-polyfill": "^6.26.0",
    "babel-PReset-es2015": "^6.24.1",
    "babel-preset-latest": "^6.24.1",
    "html-webpack-plugin": "^3.2.0",
    "webpack": "^4.8.3",
    "webpack-cli": "^2.1.3",
    "webpack-dev-server": "^3.1.4"
  },
  "dependencies": {
    "javascript-state-machine": "^3.0.1",
    "jquery": "^3.3.1"
  }
}

面向对象三要素：封装、多态、继承，子类继承父类，封装对数据的权限和保密，多态，同一个接口不同的实现，不从事后台开发很难真正理解这几个概念。

class People {
    constructor(name, age) {
        this.name = name
        this.age = age
    }
    eat() {
        alert(`${this.name} eat something`)
    }
    speak() {
        alert(`My name is ${this.name}, age ${this.age}`)
    }
}

class Student extends People {     //继承关键字extends
    constructor(name, age, number) {
        super(name, age)  //super 传给父类执行
        this.number = number
    }
    study() {
        alert(`${this.name} study`)
    }
}

let xiaoming = new Student('xiaoming', 10, 'A1')
xiaoming.study()
console.LOG(xiaoming.number)
let xiaohong = new Student('xiaohong', 11, 'A2')
xiaohong.study()

实际应用就是提取公共部分，复用代码。

关于封装，public完全开发、protected对子类开放、private对自己开放，目前es6还不支持。