安装babel
npm install babel-cli -g
配置babel
babel是用过插件或者预设来编译代码的
新建.babelrc文件
文件中输入一下内容
{ "presets": [], "plugins": [] }
安装预设
npm install --save-dev babel-preset-es2015
将preset添加到配置文件中
{ "presets": ["es2015"], "plugins": [] }
es7中的对象展开符需要一个单独的插件来实现
npm install babel-plugin-transform-object-rest-spread --save-dev
添加到配置文件中
{ "presets": ["es2015"], "plugins": ["transform-object-rest-spread"] }
转换 babel 原文件名 -o 目标文件名
示例:
转换前的代码:
let a = [1,2,3,4,5,6] let b = a.map( num => num*2 ) console.log(b) let mike = { name:'bike', age:12 } let d = {...mike,sex:"male"} console.log(d)
转换后的代码:
"use strict"; var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; var a = [1, 2, 3, 4, 5, 6]; var b = a.map(function (num) { return num * 2; }); console.log(b); var mike = { name: 'bike', age: 12 }; var d = _extends({}, mike, { sex: "male" }); console.log(d);