$timeout.js

var $$timeoutId = 0;
const deferreds = {};

function $timeout(fn, delay) {
    const timeoutId = $$timeoutId++;

    let cachedReject;
    const reject = (e) => cachedReject(e);
    const promise = new Promise((resolve, reject) => {
        cachedReject = reject;
        setTimeout(() => {
            try {
                resolve(fn());
            } catch (e) {
                reject(e);
            } finally {
                delete deferreds[timeoutId];
            }
        }, delay);
    });
    promise.reject = reject;
    promise.$$timeoutId = timeoutId;
    deferreds[timeoutId] = promise;
    return promise;
}

$timeout.cancel = (promise) => {
    if (!promise) return false;

    if (!promise.hasOwnProperty("$$timeoutId")) {
        throw new Error(
            "`$timeout.cancel()` called with a promise that was not generated by `$timeout()`."
        );
    }

    if (!deferreds.hasOwnProperty(promise.$$timeoutId)) return false;

    var id = promise.$$timeoutId;
    var deferred = deferreds[id];

    deferred.reject("canceled");
    delete deferreds[id];

    return Promise.reject(id);
};
export default $timeout;