A special page showcasing OOUI HTMLFormFieldCloner. Use in conjunction with https://gerrit.wikimedia.org/r/c/mediawiki/core/+/421373

SpecialTest.php

<?php

class SpecialTest extends FormSpecialPage {
	public function __construct() {
		parent::__construct( 'Test', '', false );
	}

	protected function getFormFields() : array {
		return [
			'clone' => [
				'type' => 'cloner',
				'label' => 'cloner',
				'help' => 'Some Help Text',
				'fields' => [
					'title' => [
						'type' => 'int',
						'help' => 'Some Help Text'
					]
				],
				'default' => [
					[ 'title' => 5 ],
					[ 'title' => 7 ]
				]
			]
		];
	}

	public function onSubmit( array $data ) {
		wfVarDump( $data );
		
		return true;
	}

	protected function getDisplayFormat() {
		$useooui = $this->getRequest()->getBool( 'useooui', true );

		return $useooui ? 'ooui' : 'table';
	}
}