Overview

Notifiers are a scalable and lightweight way to listen to changes to an object's value. Essentially they allow you to wrap any Type within a Notifier object and then listen to changes to the value.

Benefits:

• Mantain type safety / type hinting through use of generics.
• Add new fundamental object to build complex systems on top of.
• Removes the need to create getter/setters that check if the value has changed.
• Can act similar to single property Signals.

Importing

The Notifier class can be imported through notifier.Notifier

import notifier.Notifier;

Basic usage

The following is an example of how to create a Notifier of type Int and give it a default value of 5.

var notifier = new Notifier<Int>(5);

Add a standard callback listener to value changes on notifier.

notifier.add(() -> {
    trace("A: value = " + notifier.value);
});

You can also pass a callback that expects a single param of the type specified when creating the notifier, in this case 'Int'

notifier.add((value:Int) -> {
    trace("A: value = " + value);
});

Add a standard callback listener to value changes on notifier that is automatically removed after the first value change.

notifier.add(() -> {
    trace("B: value = " + notifier.value);
}, true);

Add a standard callback listener to value changes on notifier with a priority of 10 (higher priorities are called first).

notifier.add(() -> {
    trace("C: value = " + notifier.value);
}, 10);

Add a standard callback listener to value changes on notifier that is automatically removed after the first value change and with a priority of 100.

notifier.add(() -> {
    trace("D: value = " + notifier.value);
}, true, 100);

set the value of notifier to 10

notifier.value = 10;

// trace out:
// D: value = 10
// C: value = 10
// A: value = 10
// B: value = 10

set the value of notifier to 100

notifier.value = 100;

// trace out:
// C: value = 100
// A: value = 100

set the value of notifier to 200

notifier.value = 200;

// trace out:
// C: value = 200
// A: value = 200

again set the value of notifier to 200, no callbacks will be triggered, as the value hasn't changed.

notifier.value = 200;

setting requireChange to false will result in callbacks being fired regardless of if the notifer's value is changed or not when it's value is set.

notifier.requireChange = false;

set the value of notifier to 200 callbacks; C, and A will be fired in that order.

notifier.value = 200;

// trace out:
// C: value = 200
// A: value = 200

calling notifier.silentlySet(value) allows you to change the value of the notifier without any callbacks being triggered.

notifier.silentlySet(100);

Manually dispatch.

notifier.dispatch();

Extending

Extending Notifers are super simple

class MyNotifier extends Notifier<Bool>
{
	public function new()
	{
	    // passing 'true' as the default value
		super(true);
	}
}

Alternatively if you'll like to expose the Generic Type property, simply pass the Generic Type to the Notifier when extending it.

class MyNotifier<T> extends Notifier<T>
{
	public function new(?defaultValue:T)
	{
		super(defaultValue);
	}
}