一道js類的面試題，沒整明白要做什么？求答案

使用ES5 構(gòu)造函數(shù)仿寫上面的答案

function List1(){            
            this.items = [];
            for(var i =0; i<arguments.length;i++){
                this.items.push(arguments[i]);
            }
            this.length = arguments.length;
            this.add = function(){
                for(var i =0; i<arguments.length;i++){
                    this.items.push(arguments[i]);
                }
                this.length = this.items.length;
            }
        }

class List{
    constructor(...items){
        this.items = items
        this.length = items.length
    }
    add(...items) {
        this.items.push(...items)
        this.length = this.items.length
    }
}