VC Autocomplete with multiple ajax sources

utils.php

<?php

add_filter( 'vc_autocomplete_hdco_featured_featureds_callback', 'get_hdco_autocomplete_featureds', 10, 1 );
function get_hdco_autocomplete_featureds($query) {
	$query = sanitize_text_field($query);
	$items_array = [];

	$args = array(
		"post_type" => "post",
		"s" => $query
	);
	$wpquery = new WP_Query($args);
	$posts = $wpquery->get_posts();

	foreach($posts as $post) :
		$items_array[] = array( 'label' => "Article : " . get_the_title($post->ID), 'value' => 'post_' . $post->ID ) ;
	endforeach;

	$index = algolia_get_index();
	$filters = algolia_get_default_filters();

	$more = true;
	$page = 0;
	while($more) {
		$res = $index->search($query, [
			'filters' => $filters,
			'page'    => $page
		]);

		foreach($res['hits'] as $book) :
			$items_array[] = array( 'label' => "Ouvrage : " . $book['title'], 'value' => 'book_' . $book['objectID'] ) ;
		endforeach;
		$page++;
		if($res['nbPages'] == $page) {
			$more = false;
		}
	}

	return $items_array;
}

add_filter( 'vc_autocomplete_hdco_featured_featureds_render', 'hdco_autocomplete_hdco_featured_featureds_render', 10, 1 );
function hdco_autocomplete_hdco_featured_featureds_render( $query ) {
	if(!empty( $query )) {
		$index = algolia_get_index();
		$value = trim($query['value']);

		if(0 === strpos($value, 'book_')) {
			$value = substr($value, 5);
			$res = $index->getObject($value);
			if ( is_array( $res ) ) {
				$data = array();
				$data['value'] = 'book_' . $res['objectID'];
				$data['label'] = 'Ouvrage : ' . $res['title'];
				return ! empty( $data ) ? $data : false;
			}
		} else if(0 === strpos($value, 'post_')) {
			$value = substr($value, 5);

			$post = get_post($value);
			if ( is_object( $post ) ) {
				$data = array();
				$data['value'] = 'post_' . $post->ID;
				$data['label'] = 'Article : ' . get_the_title($post->ID);
				return ! empty( $data ) ? $data : false;
			}
		}
	}
	return false;
}

visual_composer.php

<?php

vc_map(
	array(
		"name" => __("Slider de mise en avant", "hdco"),
		"base" => "hdco_featured",
		"category" => "Lextenso",
		"icon" => "icon-wpb-slideshow",
		"params" => array(
			array(
				'type' => 'autocomplete',
				'heading' => __('Ouvrages ou articles', 'hdco'),
				'description' => __('Il est possible de sélectionner plusieurs éléments et de les réorganiser.', 'hdco'),
				'param_name' => 'featureds',
				'settings' => array(
					'multiple'      => true,
					'sortable'      => true,
				),
			),
			array(
				'type' => 'attach_image',
				'heading' => __('Image de fond', 'hdco'),
				'param_name' => 'background',
			),
			array(
				'param_name' => 'html',
				'type' => 'custom_markup',
				'value' => 'Ce bloc nécessite une rangée : Stretch row and content (no paddings)',
			),
		),
	)
);