Simple Events

Simple event dispatching library for PHP

Installation

Composer

The preferred way to install this extension is through Composer.

Either run

composer require yarcode/simple-events

or add

"yarcode/simple-events": "*"

to the require section of your composer.json

Usage

Via EventEmitterTrait

Attach \YarCode\Events\EventEmitterTrait to your class to make it EventEmitter

class MyClass {
    use \YarCode\Events\EventEmitterTrait;
    ...
}
$emitter = new MyClass();

Standalone EventEmitter

Or create an instance of \YarCode\Events\EventEmitter.

$emitter = new \YarCode\Events\EventEmitter();

Adding listeners

You can add callable listener for any string event name.

$emitter->addListener('TestEvent', function (\YarCode\Events\Event $event) {
    echo "{$event->name} was emitted";
});
$emitter->addListener('TestEvent', function (\YarCode\Events\Event $event) {
    echo "{$event->name} was emitted one more time";
});

Emitting events

You can emit named event with default event object.

$emitter->emit('TestEvent');
// TestEvent was emitted
// TestEvent was emitted one more time

Or you can pass \YarCode\Events\Event object to the listeners.

$event = new \YarCode\Events\Event();
$event->payload['key'] = 'value';
$emitter->emit('TestEvent', $event);
// TestEvent was emitted
// TestEvent was emitted one more time

You could pass any data as event payload. It would be passed as a first parameter to a listener callable.

$data = ['foo', 'bar'];
$emitter->emit('MixedDataEvent', $data);

Removing listeners

You can remove one concrete listener.

$callback = function (\YarCode\Events\Event $event) {
    echo "{$event->name} was emitted third time";
});
$emitter->addListener('TestEvent', $callback);
$emitter->removeListener('TestEvent', $callback);

Or remove all the listeners for the event.

$emitter->removeAllListeners('TestEvent');

Or remove all the listeners for all events.

$emitter->removeAllListeners();

Breaking the execution

Set the $event->handled property to true to stop the further listeners execution.

$emitter->addListener('TestEvent', function (\YarCode\Events\Event $event) {
    $event->handled = true;
});
$emitter->addListener('TestEvent', function (\YarCode\Events\Event $event) {
    echo "This callback for {$event->name} would never run";
});
$emitter->emit('TestEvent');

Accessing the emitter from the listener

Emitter object is being passed as a second parameter to a listener.

$emitter->addListener('TestEmitterAccessEvent', function ($data, $emitter) {
    echo "Hello"; 
    $emitter->emit('TestEmitterAccessEvent2', $data);
});
$emitter->addListener('TestEmitterAccessEvent2', function ($data) {
    echo " World";
});
$emitter->emit('TestEmitterAccessEvent');
// Hello World

License

MIT

Links

• GitHub repository
• Composer package