es6-iterator-promise

es6-iterator-promise.js

// 自行實作迭代器
const vertex1 = {
    x: 1,
    y: 2,
    z: 3,
    [Symbol.iterator]() {
        const keys = Object.keys(this);
        let i = 0;
        return {
            next: () => {
                return {
                    value: Promise.resolve(this[keys[i++]]),
                    done: keys.length === i - 1
                };
            }
        };
    }
};

for(let p of vertex1) {
    p.then(vo => {
        console.log(vo);
    });
}


// 透過產生器函式
const vertex2 = {
    x: 1,
    y: 2,
    z: 3,
    [Symbol.iterator]: function* () {
        const values = Object.values(this);
        let i = 0;
        for(let i = 0; i < values.length; i++) {
            yield Promise.resolve(values[i]);
        }
    }
};

for(let p of vertex2) {
    p.then(vo => {
        console.log(vo);
    });
}