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Field Events

You can listen to certain events and manage the state of the form. For example, you can hide some fields when another fields has a certain value.

Usage​

Update event​

You can listen to the update event:

class Example extends Field
{
    public function __construct(string $label, string $name, string $otherResource = null)
    {
        parent::__construct($label, $name, $otherResource);

        $this->onUpdate(function (ManagesForm $form, $value) {
            $form->showFields('first_name');
            $form->setState('first_name', $value[0] . '.');
        });
    }
}

Update on init​

Sometimes you need your update event to be called immediately when your form is ready (similar to an immediate watcher in Vue).

You can pass a boolean as the second argument to achieve this:

->onUpdate(function (FormState $form, $value) {
    if (!!$value) {
        $form->hideFields('mailing_plan_delay', 'mailing_delay');
        return;
    }

    $form->showFields('mailing_plan_delay', 'mailing_delay');
}, true)

Trigger a chain reaction​

In some cases, you might want to trigger a onUpdate on another field, to cause a chain reaction. There are 2 ways you can achieve this:

->onUpdate(function (FormState $form, $value) {
    // By passing `true` as the third parameter:
    $form->setState('field_1', 'some value', true);
    
    // By manually triggering:
    $form->triggerOnUpdate('field_1', 'some value');
})
warning

Be aware that having fields triggering update events on each other causes an endless loop.

On initial form request​

You can listen to the initial form request event on each field by overriding the following method.

public function onInitialFormRequest(ManagesForm $form): void
{
    dd($form->getState());
}

This will only be called once when the form is requested.