ES6（七）对象扩展

对象扩展

// 简洁表示法
let a = 1
let k = 2
let es5 = {
  a: a,
  k: k
}
let es6 = {
  a,
  k
}
console.log(es5)
console.log(es6)


let oldMethod = {
  hello: function () {
    console.log('hello')
  }
}
let es6 = {
  hello () {
    console.log('hello')
  }
}
oldMethod.hello()
es6.hello()


// 属性表达式（使用变量作为key）
let a = 'b'
let es5 = {
  a: 'c'
}
let es6 = {
  [a]: 'c'
}
// {a: "c"}
console.log(es5)
// {b: "c"}
console.log(es6)

// 是否相等
// true
console.log('字符串比较', Object.is('abc', 'abc'))
// false
console.log('数组比较', Object.is([1, 2, 3], [2, 3, 4]))
let obj1 = {a: 'a'}
let obj2 = {b: 'b'}
// false
console.log('对象比较', Object.is(obj1, obj2))
// 合并对象  属于浅拷贝 {a: "a", b: "b"}
console.log('拷贝对象', Object.assign(obj1, obj2))
let obj3 = Object.assign(obj1, obj2)
obj1 = {a: 99}
// 深拷贝 {a: "a", b: "b"}
console.log('深拷贝', JSON.parse(JSON.stringify(obj3)))
// {a: 99}
console.log(obj1)


// 循环对象
for (let [key, value] of Object.entries(obj3)) {
  console.log([key, value])
}


// 扩展运算符
let {a, b, ...c} = {
  a: 'hello',
  b: 'world',
  c: 'china',
  d: 'chengdu',
  e: 'chongqing'
}
console.log(a)
console.log(b)
// {c: "china", d: "chengdu", e: "chongqing"}
console.log(c)

 对象循环

    let myData = [
      {
        name: "公告区",
        todayposts: "0",
        fid: "2"
      },
      {
        name: "产品动态",
        todayposts: "0",
        fid: "58"
      },
      {
        name: "点小融专区",
        todayposts: "0",
        fid: "72"
      },
      {
        name: "点融",
        todayposts: "0",
        fid: "73"
      }
    ];
    Object.keys(myData).map(key => {
      console.log(myData[key]);
    });