const key = ‘test Key’
const obj = {
[key]: ‘this is key’
}
// 动态键名
obj[‘test Key’] // this is key
let a = {}
let b = a
a === b // true
let a,b = [{},{}]
let user = { name: “John”, sizes: { height: 182, width: 50 } };
let clone = Object.assign({}, user);
alert( user.sizes === clone.sizes ); // true，
对象里的第二层对象依然是引用关系