Javascript Iterator Create Array Iterator

class ArrayIterator {//from ww  w .j  av a 2s. c  o m
    constructor(array) {
        this.array = array.map(item => item).sort();
        this.index = 0;
    }

    next() {
        let result = { value: undefined, done: true };

        if (this.index < this.array.length) {
            result.value = this.array[this.index];
            result.done = false;
            this.index++;
        }

        return result;
    }
}


class TaskList {
    constructor() {
        this.tasks = [];
    }

    addTasks(...tasks) {
        this.tasks = this.tasks.concat(tasks);
    }

    [Symbol.iterator]() {
        return new ArrayIterator(this.tasks);
    }
}

let taskList = new TaskList();
taskList.addTasks('Learn JS', 'Learn ES6', 'Buy products');

for (let task of taskList) {
    console.log(task);
}