这是MyMap类的完整实现-
class MyMap { constructor() { this.container = {}; } display() { console.log(this.container); } hasKey(key) { return key in this.container; } put(key, value) { this.container[key] = value; } delete(key) { if (this.hasKey(key)) { delete this.container[key]; return true; } return false; } get(key) { return this.hasKey(key) ? this.container[key] : undefined; } keys() { return Object.keys(this.container); } values() { let values = []; for (let key in this.container) { values.push(this.container[key]); } return values; } clear() { this.container = {}; } forEach(callback) { for (let prop in this.container) { //调用回调为:callback(key,value) callback(prop, this.container[prop]); } } }