学习链接

网道教程：promise

40＋ 大厂常考 JS 手写题系列【摸鱼必备】

Promise.race

Promise.myRace = promiseArr => {
    return new Promise((resolve, reject) => {
        if (!promiseArr[Symbol.iterator]) {
            throw new TypeError(`${promiseArr} is not iterable`);
        }
        if (!Array.isArray(promiseArr)) {
            Array.from(promiseArr);
        }
        promiseArr.forEach(element => {
            Promise.resolve(element).then(resolve, reject);
        });
    });
};