d.js

import { syncIfPossible } from './syncIfPossible';
import { MINUTES } from '../helpers/date-constants';
export function LocalSyncWorker(db, cloudOptions, cloudSchema) {
    let localSyncEventSubscription = null;
    //let syncHandler: ((event: Event) => void) | null = null;
    //let periodicSyncHandler: ((event: Event) => void) | null = null;
    let cancelToken = { cancelled: false };
    let retryHandle = null;
    let retryPurpose = null; // "pull" is superset of "push"
    function syncAndRetry(purpose, retryNum = 1) {
        // Use setTimeout() to get onto a clean stack and
        // break free from possible active transaction:
        setTimeout(() => {
            if (retryHandle)
                clearTimeout(retryHandle);
            const combPurpose = retryPurpose === 'pull' ? 'pull' : purpose;
            retryHandle = null;
            retryPurpose = null;
            syncIfPossible(db, cloudOptions, cloudSchema, {
                cancelToken,
                retryImmediatelyOnFetchError: true, // workaround for "net::ERR_NETWORK_CHANGED" in chrome.
                purpose: combPurpose,
            }).catch((e) => {
                console.error('error in syncIfPossible()', e);
                if (cancelToken.cancelled) {
                    stop();
                }
                else if (retryNum < 3) {
                    // Mimic service worker sync event: retry 3 times
                    // * first retry after 5 minutes
                    // * second retry 15 minutes later
                    const combinedPurpose = retryPurpose && retryPurpose === 'pull' ? 'pull' : purpose;
                    const handle = setTimeout(() => syncAndRetry(combinedPurpose, retryNum + 1), [0, 5, 15][retryNum] * MINUTES);
                    // Cancel the previous retryHandle if it exists to avoid scheduling loads of retries.
                    if (retryHandle)
                        clearTimeout(retryHandle);
                    retryHandle = handle;
                    retryPurpose = combinedPurpose;
                }
            });
        }, 0);
    }
    const start = () => {
        // Sync eagerly whenever a change has happened (+ initially when there's no syncState yet)
        // This initial subscribe will also trigger an sync also now.
        console.debug('Starting LocalSyncWorker', db.localSyncEvent['id']);
        localSyncEventSubscription = db.localSyncEvent.subscribe(({ purpose }) => {
            try {
                syncAndRetry(purpose || 'pull');
            }
            catch (err) {
                console.error('What-the....', err);
            }
        });
        //setTimeout(()=>db.localSyncEvent.next({}), 5000);
    };
    const stop = () => {
        console.debug('Stopping LocalSyncWorker');
        cancelToken.cancelled = true;
        if (localSyncEventSubscription)
            localSyncEventSubscription.unsubscribe();
    };
    return {
        start,
        stop,
    };
}