贪心学院机器学习中级课
index.js + main.js ***********************
let a = 1
console.log(a)
let b = 1
console.log(b)
**********************npm install --save-dev babel-loader babel-core babel-preset-env webpack // 使用 webpack 3.x babel-loader 7.x | babel 6.x，注意 github 点击[链接])vi webpack.config.js
