@nativescript/shared-notification-delegate

This project aims to prevent the shortcomings that come from the iOS implementation of only allowing a single delegate.

Installation 

npm install @nativescript/shared-notification-delegate

Usage

Import SharedNotificationDelegate and add Observers

import { SharedNotificationDelegate } from '@nativescript/shared-notification-delegate';
...

SharedNotificationDelegate.addObserver({
    delegateUniqueKey: "myUniqueKey", // ensures uniqueness, if not set or is null/undefined, allows multiple of the same
    userNotificationCenterWillPresentNotificationWithCompletionHandler: (notificationCenter, notification, handler, stop, next) => {

        console.log("notification received by observer");
        // is this notification something I should handle?
        if (shouldHandleThis) {
            // do stuff
            // intercept it and show alert
            handler(UNNotificationPresentationOptions.Alert);
            return;
        }
        // not mine, next should handle
        next();
    }
});

API

SharedNotificationDelegate Methods

MethodReturnsDescription
addObserver(observer: DelegateObserver, priority?: number)voidAdds a delegate observer of a certain priority (lower means first). Default priority is 100.
removeObserver(observer: DelegateObserver)voidRemoves a DelegateObserver
removeObserverByUniqueKey(key: any)voidRemoves a DelegateObserver by its unique key

DelegateObserver Interface

A DelegateObserver can implement 3 methods from UNUserNotificationCenterDelegate with the addition of some details:

interface DelegateObserver {
  userNotificationCenterDidReceiveNotificationResponseWithCompletionHandler?(
    center: UNUserNotificationCenter,
    response: UNNotificationResponse,
    completionHandler: () => void,
    next: () => void
  ): void

  userNotificationCenterOpenSettingsForNotification?(
    center: UNUserNotificationCenter,
    notification: UNNotification,
    stop: () => void,
    next: () => void
  ): void

  userNotificationCenterWillPresentNotificationWithCompletionHandler?(
    center: UNUserNotificationCenter,
    notification: UNNotification,
    completionHandler: (p1: UNNotificationPresentationOptions) => void,
    next: () => void
  ): void

  /**
   * if set to not null/undefined, will ensure only one is registered
   */
  delegateUniqueKey?: any
}

  • All the functions that are parameters of the DelegateObserver object's methods are called asynchronously in a chain.

  • Calling a completionHandler immediately stops the observer chain. next() must be called if the method will not be handling the notification.

  • Calling stop() on userNotificationCenterOpenSettingsForNotification prevents the event from bubbling to the rest.

  • Only one method will be processed at a time, this means you can take as long as you want (including making http calls, for example), as long as you just call completionHandler, stop and next when you're finished.

  • If a DelegateObserver has a delegateUniqueKey, the SharedNotificationDelegate will ensure only the latest copy of the observer is present. This is especially useful if debugging with HMR, which may add multiple observers on application reload.

License

Apache License Version 2.0, January 2004