ES6 新增了很多特性，这里罗列了一些常用的，供大家参考。

ES6常用方法罗列

let、count

iterable (迭代器类型): Array 、 Map 、 Set ,可以通过 for … of 遍历

箭头函数

test=(param)=>{}

promise

向对象添加属性

const a ={id:1};
const b ={...a , pwd :"123"};// a 克隆成 b ,并在 b 中添加 pwd 属性

合并对象

//方法一
 const a ={id:1};
 const b ={ pwd :"123"};
 constc ={...a, ...b };// ...为扩展运算符
//方法二
 let obj1={ a :1}; 
 let obj2={ b :2}; 
 let obj3={ c :3};
 let obj4= Object.assign (obj1,obj2,obj3);
 console.log(obj1);//{ a :1, b :2, c :3}
 console.1og(obj2);//{ b :2}
 console.log(obj3);//{ c :}
 console.log(obj4);//{ a :1, b :2, c :3}

删除属性

let old ={
   id :1,
   age :21,
   name :"zhg" 
};
//方法一 
let {
  name,
  ...news
}= old; 
console.log(news);//{ id :1, age :21}

//方法二
let newS =(({ id , age })=>({ id , age }))( old ); 
console.log(newS);//{ id :1, age :21}

调整属性位置

let old ={
  age :21,
  name :"zhg",
  id :1
};
let news ={ name : undefined , ...old };
// let news ={...old , name }//{ age :21, id :1,name:"zhg"}
console.log(news);//{ name :"zhg", age :21, id :1}
// let organize = object =>({ id : undefined ,.. object });
// let news= organize(old);
// console.log(news);

重命名对象属性

let old ={
  age :21,
  name :"zhg",
  id :1
};
//方法一
let rename =({ id, ...old })=>({ ID : id, ...old });
let news = rename(old);
console.1og(news);//{ ID :1, age :21, name :"zhg"}

//方法二
let { id : IDD , name : Name }= old;
console.log(IDD);//1
//不能获取改变值的对象,只能获取改变名称的值

条件属性

let old ={
  age :21,
  name :"zhg",
  id :1
};
let pwd ="pwd";
let blank ="";
let news={...old , ...(pwd &&{ pwd }), ...( blank &&{ blank })};
console.log(news);//{ age :21, name :"zhg", id :1, pwd :"pwd"}

数组元素位置交换

let list =[0,1,2,3,4,5];
[list[1],list[3],list[5]]=[list[5], list[1], list[3]];
console.log(list);//[0,5,2,1,4,3]

字符串新增方法

• includes(str,start)
• startsWith(str, start)
• endsWith(str, length)

let str = "ABCDEFG";
let result = str.startsWith ("B",2);
console.log(result);//0: false ;1:ture;2:false

对象赋值解构

//数组
let [a, b, c, d ]=[1,2,3,4];
console.log(a);// a =1; b =2; c =3; d =4;
//对象
let obj ={
  name : "zhg",
  say(){ console.log("zhg")}
}
// ==> let obj ={ name :"zhg", say :()=> console.log("zhg")}
obj.say();// console.log: zhg 

函数传参解构

let arr=["abc",2,3]; 
function fn1([a, b, c]){
  console.log(a);// abc 
  console.log(b);// 2 
  console.log(c);//3
}
fn1(arr);

// 暂不支持如下方法解构
let obj = {
  a:"a",
  B:"b",
  c:[1,2,3]
}
let {a, B, c:[d,e,f]} = obj
console.log(e);// 不支持

数组去重

let arr =[1,2,3,4,5,4,3]; 
let set = new Set(arr);
let newArr = Array.from(set);
console.1og(newArr);//[1,2,3,4,5]

数组拷贝

let arr = [1,2,3];
let arr2= arr;
let arr3=[ ...arr ];
console.log(arr2===arr);// true 是一个数组
console.log(arr3===arr);// false不是同一个数组

字符串转数组

let str = "abcd";
let arr =[...str];
console.log(arr);//['a', 'b', 'c','d'];