Wire::changed() method

Hookable method that is called whenever a property has changed while change tracking is enabled.

  • Enables hooks to monitor changes to the object.
  • Do not call this method directly, as the Wire::trackChange() method already does so.
  • Descending classes should call $this->trackChange('name', $oldValue, $newValue); when a property they are tracking has changed.

Usage

// basic usage
$wire->changed(string $what);

// usage with all arguments
$wire->changed(string $what, mixed $old = null, mixed $new = null);

Arguments

NameType(s)Description
whatstring

Name of property that changed

old (optional)mixed

Previous value before change

new (optional)mixed

New value


Hooking Wire::changed(…)

You can add your own hook events that are executed either before or after the Wire::changed(…) method is executed. Examples of both are included below. A good place for hook code such as this is in your /site/ready.php file.

Hooking before

The 'before' hooks are called immediately before each Wire::changed(…) method call is executed. This type of hook is especially useful for modifying arguments before they are sent to the method.

$this->addHookBefore('Wire::changed', function(HookEvent $event) {
  // Get the object the event occurred on, if needed
  $Wire = $event->object;

  // Get values of arguments sent to hook (and optionally modify them)
  $what = $event->arguments(0);
  $old = $event->arguments(1);
  $new = $event->arguments(2);

  /* Your code here, perhaps modifying arguments */

  // Populate back arguments (if you have modified them)
  $event->arguments(0, $what);
  $event->arguments(1, $old);
  $event->arguments(2, $new);
});

Hooking after

The 'after' hooks are called immediately after each Wire::changed(…) method call is executed. This type of hook is especially useful for modifying the value that was returned by the method call.

$this->addHookAfter('Wire::changed', function(HookEvent $event) {
  // Get the object the event occurred on, if needed
  $Wire = $event->object;

  // An 'after' hook can retrieve and/or modify the return value
  $return = $event->return;

  // Get values of arguments sent to hook (if needed)
  $what = $event->arguments(0);
  $old = $event->arguments(1);
  $new = $event->arguments(2);

  /* Your code here, perhaps modifying the return value */

  // Populate back return value, if you have modified it
  $event->return = $return;
});

See Also


Wire methods and properties

API reference based on ProcessWire core version 3.0.209

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