PHP method to work inside WordPress to return post data array

getPostsData.php

/**
 * Get Posts
 *
 * build array of post data
 *
 * @param string $post_type - could be a custom post type. defaults to 'post'
 * @param string $return_number - defaults to all available posts
 * @return array
 */
function getPostsData(string $post_type, string $return_number): array {
    $args = [
        'post_type' => ($post_type) ? $post_type : 'post',
        'post_status' => 'publish',
        'posts_per_page' => ($return_number) ? $return_number : -1,
        'order' => 'DSC'
    ];

    $the_query = new WP_Query($args);
    $postData = [];

    if ($the_query->have_posts()) :
        while ($the_query->have_posts()) : $the_query->the_post(); 
		$postData[get_the_ID()] = [
			'title' => the_title(),
			'date' => the_date(),
			'excerpt' => the_excerpt(),
			'featured_image' => getFeaturedImage(get_the_ID(),'medium'),
			'permalink' => the_permalink()
		];
    endwhile; endif;
    wp_reset_postdata(); //needed??

    return $postData;
}