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Created by Josh Morony

createNotifier provides a way to manually trigger signal re-computations by referencing the created notifier signal. Common use cases for this include:

  • Manually triggering a “refresh” and reacting to it
  • Mutating a Map and having a way to react to that map changing
  • Triggering a re-computation on some kind of event/life cycle hook

It simply creates a standard signal that has its value incremented by 1 every time notify is called. This means the signal value will change and any effect or computed that references this signal will be re-computed.

You can create a notifier like this:

import { createNotifier } from 'ngxtension/create-notifier';
refreshNotifier = createNotifier();

You can trigger the signal update like this:


Then you can trigger a re-computation of any computed or effect (or derivedAsync from ngxtension) by referencing the signal returned on listen:

effect(() => {
// whatever code you want to run whenever
// refreshNotifier.notify() is called

An important thing to keep in mind is that an effect will also run once initially before notify() is explicitly called. Since the version number used internally for the signals value begins with 0 you can avoid this “init” behaviour by setting up your effect like this instead:

effect(() => {
if (refreshNotifier.listen()) {
// Will NOT run on init
// whatever code you want to run whenever
// refreshNotifier.notify() is called

With this set up, the if will initially fail because the value of refreshNotifier.listen() will initially be 0, but once notify has been explicitly called the if condition will always pass because the value of the signal will always be above 0.