webdetector/ts/index.ts

import * as plugins from './webdetector.plugins.js';

import { Platform } from './webdetector.classes.platform.js';

export interface IWebDetectorOptions {
  checkOnlineUrl: string;
}

export class WebDetector {
  // subclasses
  public platform = new Platform();

  options: IWebDetectorOptions;
  private onlineObservableIntake = new plugins.smartrx.ObservableIntake();
  public onlineObservable = this.onlineObservableIntake.observable.pipe(
    plugins.smartrx.rxjs.ops.throttleTime(10000)
  );
  latestState: 'online' | 'offline' = 'online';

  constructor(optionsArg: IWebDetectorOptions) {
    this.options = optionsArg;
  }

  /**
   *
   */
  async isOnline() {
    let reachesInternet: boolean = false;
    const controller = new AbortController();
    const fetchPromise = fetch(this.options.checkOnlineUrl, { signal: controller.signal });
    const timeout = setTimeout(() => {
      controller.abort();
    }, 1000);

    await fetchPromise
      .then(async (response) => {
        reachesInternet = true;
      })
      .catch((err) => {
        // console.log(`request to ${this.options.checkOnlineUrl} failed}`)
      });
    const latestLocalState = (() => {
      if (reachesInternet) {
        return 'online';
      } else {
        return 'offline';
      }
    })();
    if (latestLocalState !== this.latestState) {
      this.onlineObservableIntake.push(this.latestState);
    }
    this.latestState = latestLocalState;
    return reachesInternet;
  }

  private periodicChecksRunning = false;

  public async startPeriodicChecks() {
    this.periodicChecksRunning = true;
    while (this.periodicChecksRunning) {
      await this.isOnline();
      await plugins.smartdelay.delayFor(3000);
    }
  }

  public async stopPeriodicChecks() {
    this.periodicChecksRunning = false;
  }
}