详解javascript中的babel到底是什么

let numbers = [1,2,3];
let dou = numbers.map((number)=>number*2);
console.log(dou);

{
  "plugins":[ ],
  "presets":[ ]
}

npm i babel-preset-es2015 --save-dev

{
  "plugins":[ ],
  "presets":["es2015"]
}

var numbers = [1, 2, 3];
var dou = numbers.map(function (number) {
 return number * 2;
});
console.log(dou);

npm i babel-plugin-transform-object-rest-spread --save-dev

{
  "plugins":["transform-object-rest-spread"],
  "presets":["es2015"]
}

let mike = {name:'mike',age:40};
mike={...mike,sex:'男'};
console.log(mike);

'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 mike = { name: 'mike', age: 40 };
mike = _extends({}, mike, { sex: '男' });
console.log(mike);