onesignal-web-sdk/src/managers/SessionManager.ts

Web push notifications from OneSignal.

import SdkEnvironment from '../managers/SdkEnvironment';
import { WindowEnvironmentKind } from '../models/WindowEnvironmentKind';
import Log from '../libraries/Log';

export class SessionManager {
  private static SESSION_STORAGE_KEY_NAME = 'onesignal-pageview-count';
  private incrementedPageViewCount: boolean = false;

  getPageViewCount(): number {
    try {
      /*
        sessionStorage may be supported by the browser but may not be available
        as an API in incognito mode and in cases where the user disables
        third-party cookies on some browsers.
       */
      const pageViewCountStr = sessionStorage.getItem(SessionManager.SESSION_STORAGE_KEY_NAME);
      const pageViewCount = pageViewCountStr ? parseInt(pageViewCountStr) : 0;
      if (isNaN(pageViewCount)) {
        return 0;
      } else {
        return pageViewCount;
      }
    } catch (e) {
      /*
        If we're in incognito mode or sessionStorage is otherwise unsupported,
        pretend we're starting our first session.
       */
      return 0;
    }
  }

  setPageViewCount(sessionCount: number) {
    try {
      sessionStorage.setItem(SessionManager.SESSION_STORAGE_KEY_NAME, sessionCount.toString());

      if (SdkEnvironment.getWindowEnv() === WindowEnvironmentKind.OneSignalSubscriptionPopup) {
        // If we're setting sessionStorage and we're in an Popup, we need to also set sessionStorage on the
        // main page
        if (OneSignal.subscriptionPopup) {
          OneSignal.subscriptionPopup.message(OneSignal.POSTMAM_COMMANDS.SET_SESSION_COUNT);
        }
      }
    } catch (e) {
      /*
        If sessionStorage isn't available, don't error.
       */
    }
  }

  /**
   * Increments the session count at most once for the current page view.
   *
   * A flag is set to prevent incrementing the session count more than once for
   * the current page view. If the page is refreshed, this in-memory variable
   * will be automatically reset. Because of this, regardless of the number of
   * times this method is called on the current page view, the page view count
   * will only be incremented once.
   */
  incrementPageViewCount() {
    if (this.incrementedPageViewCount) {
      // For this method, we don't want to increment the session count more than
      // once per pageview
      return;
    }

    const newCount = this.getPageViewCount() + 1;
    this.setPageViewCount(newCount);
    Log.debug(`Incremented page view count to ${newCount}.`);
    this.incrementedPageViewCount = true;
  }

  simulatePageNavigationOrRefresh() {
    this.incrementedPageViewCount = false;
  }

  /**
   * Returns true if this page is running OneSignal for the first time and has
   * not been navigated or refreshed.
   */
  isFirstPageView() {
    return this.getPageViewCount() === 1;
  }
}