猫史档案馆

class Bag {
    constructor(initialValue = []) {
        this.item = new Map(initialValue);
    }
    addThings(name, num) {
        this.item.has(name) ? this.item.set(name, this.item.get(name) + num) : this.item.set(name, num)
    }
    delThings(name, num) {
        this.item.has(name) ? this.item.set(name, this.item.get(name) - num) :null;
        this.item.get(name) <= 0 ? this.item.delete(name) : null
    }
    hasThings(name, num = 1) {
        return (this.item.get(name) || 0) >= num;
    }
    length() {
        return this.item.size
    }
    clear() {
        this.item.clear()
    }
    showBag() {
        return Array.from(this.item, ([name, num]) => `${name} × ${num}件`);
    }
}

又氵了一个帖（确信