wiki.techinc.nl/includes/htmlform/fields/HTMLSelectNamespace.php

<?php
/**
 * Wrapper for Html::namespaceSelector to use in HTMLForm
 */
class HTMLSelectNamespace extends HTMLFormField {

	/** @var string|null */
	protected $mAllValue;

	public function __construct( $params ) {
		parent::__construct( $params );

		$this->mAllValue = array_key_exists( 'all', $params )
			? $params['all']
			: 'all';
	}

	public function getInputHTML( $value ) {
		return Html::namespaceSelector(
			[
				'selected' => $value,
				'all' => $this->mAllValue
			], [
				'name' => $this->mName,
				'id' => $this->mID,
				'class' => 'namespaceselector',
			]
		);
	}

	public function getInputOOUI( $value ) {
		return new MediaWiki\Widget\NamespaceInputWidget( [
			'value' => $value,
			'name' => $this->mName,
			'id' => $this->mID,
			'includeAllValue' => $this->mAllValue,
		] );
	}

	protected function getOOUIModules() {
		// FIXME: NamespaceInputWidget should be in its own module (probably?)
		return [ 'mediawiki.widgets' ];
	}

	protected function shouldInfuseOOUI() {
		return true;
	}
}