es6 set的使用

常用属性

size 返回set实例的成员总数

let arr = [1,2,3,4,5];
let set = new Set(arr);
console.log(set.size)  //5

操作方法(用于数据操作)“add(value)”、“delete(value)”、“has(value)”、clear()；

1.add()

let set = new Set([1,2,3,4,5]);
//添加数据
let addSet = set.add(6);
console.log(addSet); // {1,2,3,4,5,6}

2.delete()

let set = new Set([1,2,3,4,5]);
//添加数据
let addSet = set.delete(5);
console.log(addSet); // {1,2,3,4}

3.has()

let set = new Set([1,2,3,4,5]);
//添加数据
let addSet = set.has(5);
console.log(addSet); // true
let addSet = set.has(6);
console.log(addSet); // false

4.clear()

let set = new Set([1,2,3,4,5]);
//添加数据
let addSet = set.clear();
console.log(addSet); // {}

set中将字符串转为数组

let set = new Set([1,2,3,4,5]);
console.log(set);  //  {1,2,3,4,5}
let arrSet = [...set];
console.log(arrSet);  //  [1,2,3,4,5]
console.log([...ser]);  //  [1,2,3,4,5]
console.log([...new Set([1,2,3,4,5])]);  //  [1,2,3,4,5]