ES6 中的解构数组和对象

Posted 2020-11-22 webmc

1. 解构对象

    var people = {
      name:‘jarry‘,
      age:15
    }

    const {name,age} = people;
    console.log(name,age)   //jarry 15
//例子
    function who({name,age}){
      return `${name}的年龄是${age}`;
    }

    console.log(who(people))  //jarry的年龄是15

2.解构数组

var names = ["tom","jarry","jack"]
    //返回数组元素
    const [name1,name2,name3] = names;
    console.log(name1,name2,name3)  //tom jarry jack
    // 返回数组个数
    const {length} = names;
    console.log(length)  // 3
    // 结合展开运算符
    const [name,...rest] = names
    console.log(name)     // tom
    console.log(...rest)   // jarry jack

3.应用场景

    // 将二维数组转为数组对象
    var points = [
      [2,3],
      [10,5],
      [7,2]
    ]

    let newPoints = points.map(([x,y]) => {
      return {x,y}
    })

    console.log(newPoints)  //  [{x: 2, y: 3},{x: 10, y: 5},{x: 7, y: 2}]