//宣告一個物件
        const banji = {
            name: "終極一班",
            stus: [
                'xiaoming',
                'xiaoning',
                'xiaotian',
                'knight'
            ],
            [Symbol.iterator]() {
                //索引變數
                let index = 0;
                
 
//
                let _this = this;
                return {
                    next: function () {
                        if (index < _this.stus.length) {
                            const result = { value: _this.stus[index], done: false };
                            //下標自增
                            index++;
                            
 
//返回結果
                            return result;
                        }else{
                            return {value: undefined, done: true};
                        }
                    }
                };
            }
        }

        //遍歷這個物件 
        for (let v of banji) {
            console.log(v);
        }