get_available_post_mime_types()

get_available_post_mime_types( string $type = 'attachment' ): string[]

function get_available_post_mime_types( $type = 'attachment' ) {
	global $wpdb;

	/**
	 * Filters the list of available post MIME types for the given post type.
	 *
	 * @since 6.4.0
	 *
	 * @param string[]|null $mime_types An array of MIME types. Default null.
	 * @param string        $type       The post type name. Usually 'attachment' but can be any post type.
	 */
	$mime_types = apply_filters( 'pre_get_available_post_mime_types', null, $type );

	if ( ! is_array( $mime_types ) ) {
		$mime_types = $wpdb->get_col( $wpdb->prepare( "SELECT DISTINCT post_mime_type FROM $wpdb->posts WHERE post_type = %s AND post_mime_type != ''", $type ) );
	}

	// Remove nulls from returned $mime_types.
	return array_values( array_filter( $mime_types ) );
}