Answer 1

@GuidingStarKe

Answer 2

npm有个 zhuangbility

Answer 3

function myPromiseAny(arr) {
    return new Promise((resolve, reject) => {
        let pendingCount = arr.length;
        const error = new Error("all promise were rejected");
        error.errors = new Array(arr.length);

        function resolveHandler(v) {
            pendingCount -= 1;
            resolve(v);
        }
        function rejecthandler(index) {
            return function (e) {
                pendingCount -= 1;
                error.errors[index] = e;
                if (pendingCount === 0) {
                    reject(error);
                }
            }
        }

        arr.forEach((arrItem, index) => {
            Promise.resolve(arrItem).then(resolveHandler).catch(rejecthandler(index));
        });
    });
}