@reallyland/polling-observer/dist/polling-observer.js

async function delayUntil(delay = 0) {
    return new Promise((yay) => {
        const delayNum = 'number' === typeof (delay) ? +delay : 0;
        if (delayNum < 1)
            yay();
        else
            setTimeout(yay, delay);
    });
}

async function globalPerformance() {
    return ('undefined' !== typeof (window) ? window : global).performance;
}

class PollingMeasure {
    constructor(name, duration, startTime) {
        this.name = name;
        this.duration = duration;
        this.startTime = startTime;
        this.entryType = 'polling-measure';
    }
    toJSON() {
        return {
            duration: this.duration,
            entryType: this.entryType,
            name: this.name,
            startTime: this.startTime,
        };
    }
}

function isPromise(r) {
    return 'function' === typeof (r.then);
}
class PollingObserver {
    constructor(conditionCallback) {
        this.conditionCallback = conditionCallback;
        this._forceStop = false;
        this._records = [];
        this._isPolling = false;
        if ('function' !== typeof (conditionCallback)) {
            throw new TypeError(`'conditionCallback' is not defined`);
        }
    }
    disconnect() {
        this._forceStop = true;
        if (!this._isPolling)
            this._records = [];
    }
    async observe(callback, options) {
        this._forceStop = false;
        const { interval, timeout } = options || {};
        const isValidInterval = 'number' === typeof (interval) && interval > 0;
        const obsTimeout = 'number' === typeof (timeout) ? +timeout : -1;
        const obsInterval = isValidInterval ? +interval : -1;
        const perf = await globalPerformance();
        const isInfinitePolling = obsTimeout < 1;
        const records = this._records;
        const onfinishCallback = this.onfinish;
        const conditionCallback = this.conditionCallback;
        let totalTime = 0;
        let value = void 0;
        let i = 0;
        let status = 'finish';
        let result = {};
        try {
            polling: while (true) {
                if (this._forceStop)
                    break polling;
                this._isPolling = true;
                const conditionResult = conditionCallback(value, records, this);
                const didConditionMeet = isPromise(conditionResult) ?
                    await conditionResult : conditionResult;
                const didTimeout = isInfinitePolling ? false : totalTime >= obsTimeout;
                if (didTimeout || didConditionMeet) {
                    status = didTimeout ? 'timeout' : status;
                    break polling;
                }
                const startAt = perf.now();
                const r = callback();
                value = isPromise(r) ? await r : r;
                const endAt = perf.now();
                const duration = endAt - startAt;
                const timeLeft = isValidInterval ? obsInterval - duration : 0;
                records.push(new PollingMeasure(`polling:${i}`, duration, startAt));
                totalTime += (duration > obsInterval ? duration : obsInterval);
                i += 1;
                if (timeLeft > 0)
                    await delayUntil(timeLeft);
            }
            result = { status, value };
        }
        catch (e) {
            result = { status: 'error', reason: e };
        }
        finally {
            const recordsSlice = records.slice();
            if (this._forceStop)
                this._records = [];
            this._isPolling = this._forceStop = false;
            if ('function' === typeof (onfinishCallback)) {
                onfinishCallback(result, recordsSlice, this);
            }
        }
    }
    takeRecords() {
        return this._records;
    }
}

export default PollingObserver;
export { PollingObserver };
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