/*js设计模式——迭代器模式*/

class Iterator {

    constructor(container) {

        this.list = container.list;

        this.index = 0;

    }

    // next 判断下一项还有则继续追加

    next() {

        if (this.hasNext()) {

            return this.list[this.index++];

        }

        return null;

    }

    // hasNext 判断是否还有下一项

    hasNext() {

        if (this.index >= this.list.length) {

            return false;

        }

        return true;

    }

}

class Container {

    constructor(list) {

        this.list = list;

    }

    // 生成遍历器

    getIterator() {

        return new Iterator(this);

    }

}

let arr = [1, 2, 3, 4, 5, 6];

let container = new Container(arr);

let iterator = container.getIterator()

while(iterator.hasNext()){

    console.log(iterator.next())

}