Check for PWA application updates in Angular

check-for-update.service.ts

import { ApplicationRef, Injectable } from '@angular/core';
import { SwUpdate } from '@angular/service-worker';
import { concat } from 'rxjs/observable/concat';
import { interval } from 'rxjs/observable/interval';
import { first } from 'rxjs/operators';
import { NGXLogger } from 'ngx-logger';
import { environment } from 'environments/environment';
import { DialogService } from './dialog.service';

@Injectable()
export class CheckForUpdateService {

    constructor(
        private appRef: ApplicationRef,
        private swUpdate: SwUpdate,
        private _logger: NGXLogger,
        private _dialog: DialogService) { }

    init() {
        if (this.swUpdate.isEnabled) {
            this.promptOnUpdateAvailable();
            this.checkForUpdateAfterInterval(environment.checkForUpdateInterval);
        }
    }

    private promptOnUpdateAvailable() {
        this.swUpdate.available.subscribe((event) => {
            this._logger.info('Current version is', event.current);
            this._logger.info('Available version is', event.available);

            this._dialog
                .showConfirmDialog(
                    'Update Available!',
                    'A new version of EdgeConnect is available. Please update now.',
                    { positiveButtonLabel: 'Update', negativeButtonLabel: 'Not Now' }).
                result.then((data) => {
                    if (data === true) {
                        this._logger.info('User continued with update', event.available);
                        window.location.reload();
                    } else {
                        this._logger.info('User choose to skip update', event.available);
                    }
                }).catch((err) => {
                    this._logger.log(err);
                });
        });
    }

    /**
     * Check for updates after interval specified in minutes
     * @param minutesInterval interval in minutes
     */
    private checkForUpdateAfterInterval(minutesInterval: number) {
        this._logger.info('Check for updates initiated!');
        // Allow the app to stabilize first, before starting polling for updates with `interval()`.
        const appIsStable$ = this.appRef.isStable.pipe(first(isStable => isStable === true));
        const everyInterval$ = interval(minutesInterval * 60 * 1000);
        const everyIntervalOnceAppIsStable$ = concat(appIsStable$, everyInterval$);

        everyIntervalOnceAppIsStable$.subscribe(() => {
            this.swUpdate.checkForUpdate();
        });
    }
}