数组对象与Set和Map 数据结构的一些常见转换

Posted 2022-02-08 LyCat_00

Set

1. Set 转为数组

Array.from 可以将Set 结构转为数组：

  const items = new Set([1,2,3,4,5]);
  const array = Array.from(items);

2. Set 实现数组去重

const array = [1,20,20,3,4];
const removeDuplicate = [...new Set(array)];

3. 去除字符串里面的重复字符串

[...new Set('abdjfjdd')].join('')

Map

1. Map 转为数组

const mMap = new Map([[true,2],[foo:3,['acvv']]])
const arr = [...mMap]

2. Map 转对象

  const mapToObj = (strMap) => 
    let obj = Object.create(null);
    for (let [k,v] of strMap) 
      obj[k] = v;
    
    return obj;
  

3. 对象转为Map

第一种：对象转Map 可以通过Object.entries()

  let obj = "a":1, "b":2;
  let map = new Map(Object.entries(obj));

第二种：for 遍历

  const objToMap = (obj) => 
    let strMap = new Map();
    for (let k of Object.keys(obj)) 
      strMap.set(k, obj[k]);
    
    return strMap;