Helper functions to move scripts enqueued by WordPress or plugins to bottom

h1-move-script-to-bottom.php

<?php

/**
 * Move script(s) to bottom
 * 
 * @param string|array $script_handles Script handles to be moved to bottom
 * @param array        $args           Additional arguments. Defaults to array( 'move_deps' => false ). Set to true to also move scripts dependencies.
 */
function h1_move_script_to_bottom( $script_handles, $args = array() ) {
	$defaults = array(
		'move_deps' => false
	);

	$args = wp_parse_args( $args, $defaults );

	// Make it an array if not already.
	if ( ! is_array( $script_handles ) ) {
		$script_handles = array( $script_handles );
	}

	global $wp_scripts;

	// Loop through scripts about to be moved.
	foreach ( $script_handles as $script_handle ) {
		// Check if the script is enqueued.
		if ( ! wp_script_is( $script_handle ) ) {
			continue;
		}

		if ( $args['move_deps'] ) {
			// Get script data.
			$script = $wp_scripts->registered[ $script_handle ];

			// Move script's dependencies to bottom.
			foreach ( $script->deps as $dep ) {
				$wp_scripts->add_data( $dep, 'group', 1 );
			}
		}

		// Move the main script to bottom.
		$wp_scripts->add_data( $script_handle, 'group', 1 );
	}
}

/**
 * Move script(s) to bottom if none of scripts as the second parameter are enqueued.
 * 
 * @param string|array $script_handles            Script handles to be moved to bottom
 * @param string|array $dependency_script_handles Script handles that cannot be enqueued
 */
function h1_move_script_to_bottom_if_another_not_enqueued( $script_handles, $dependency_script_handles ) {
	// Make it an array if not already
	if ( ! is_array( $dependency_script_handles ) ) {
		$dependency_script_handles = array( $dependency_script_handles );
	}

	// Don't do anything if any of the scripts are enqueued
	foreach ( $dependency_script_handles as $dependency_script_handle ) {
		if ( wp_script_is( $dependency_script_handle ) ) {
			return;
		}
	}

	h1_move_script_to_bottom( $script_handles, array( 'move_deps' => true ) );
}

// Below is an example how one could use the above helper functions.
// add_action call is disabled to prevent copy paste mistakes.
 
/**
 * Moves Gravity Forms script to bottom. Moves jQuery to bottom as well,
 * unless Gravity Forms scrips are enqueued. Which means we cannot move jQuery,
 * because GF assumes it is loaded in header. Stupid Gravity Forms.
 */
function h1_move_scripts() {
	h1_move_script_to_bottom_if_another_not_enqueued(
		array(
			'jquery-core',
			'jquery-migrate'
		),
		'gform_gravityforms'
	);

	h1_move_script_to_bottom(
		array(
			'jquery_json',
			'gform_placeholder',
			'gform_gravityforms',
			'optin-monster-api-script'
		)
	);
}

// add_action( 'wp_enqueue_scripts', 'h1_move_scripts', 99 );