9.11 新类型(了解)

1、map

const map = new Map([
    ['name', '张三'],
    ['title', 'author']
]);
let name = map.get('name');
let title = map.get('title');
console.log(name, title);

2、set

let arr = [5, 1, 2, 2, 2, 3, 2, 6, 7];
let set = new Set(arr);
console.log('set', set);
arr = [...set];
console.log('arr', arr);

3、symbol

// demo3.1
let s1 = Symbol('aa');
let s2 = Symbol('aa');
console.log(s1 === s2); // false
// demo3.2
let username = Symbol('username');
let age = Symbol('age');
let obj1 = {
    username: '张三',
    age: 16
}
let obj2 = {
    [username]: '张三',
    [age]: 20
}
let obj = {
    ...obj1,
    ...obj2
}
console.log(obj);