wp-generate-script-bundle-manifest.php

<?php
/**
 * Generate ordered list of scripts according to their dependencies and whether they are enqueued for the header or footer.
 * This may be called in a Grunt task to obtain the list of assets to concatenate and minify. 
 * Usage: wp eval-file wp-generate-script-bundle-manifest.php
 * Author: Weston Ruter, XWP
 */

wp_enqueue_scripts();
wp_scripts()->all_deps( wp_scripts()->queue );

$groups = array(
	0 => 'head',
	1 => 'footer',
);
$group_assets = array();
foreach ( $groups as $group => $group_name ) {
	$assets = array();
	foreach ( wp_scripts()->to_do as $key => $handle ) {
		if ( ! in_array( $handle, wp_scripts()->done, true ) && isset( wp_scripts()->registered[ $handle ] ) ) {

			if ( 0 === $group && wp_scripts()->groups[ $handle ] > 0 ) {
				wp_scripts()->in_footer[] = $handle;
				continue;
			}

			if ( false === $group && in_array( $handle, wp_scripts()->in_footer, true ) ) {
				wp_scripts()->in_footer = array_diff( wp_scripts()->in_footer, (array) $handle );
			}

			unset( wp_scripts()->to_do[ $key ] );
			wp_scripts()->done[] = $handle;
			$assets[ $handle ] = wp_scripts()->registered[ $handle ]->src;
		}
	}
	$group_assets[ $group_name ] = array_filter( $assets );
}

echo json_encode( $group_assets, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES );