Fix for ACF + WP Media Folder (ACF admin stops working due to javascript error in WP Media Folder)

functions.php

<?php

/**
 * Fixes issue where JS is halted on ACF admin pages when WP Media Folder is activated.
 * 
 * These are the versions of the plugins I had when I tried
 * - WP Media Folder - 1.0.4
 * - Advanced Custom Fields Pro - (5.1.8, 5.2.1)
 * 
 * 
 * NOTES
 * -----
 * 
 * WP Media Folder registers with the handle 'script' which is bad practice since the handle is 
 * really generic and can easily be overwritten/used by other plugins or themes as well.
 * 
 * http://codex.wordpress.org/Function_Reference/wp_register_script#Parameters
 * 
 * WP Media Folder should also have a check that window.wp.Uploader (js) exists before trying to access it.
 * 
 * @return void
 **/
function hampusn_admin_enqueue_scripts() {
  global $typenow;
  
  $wp_media_folder_is_hooked = has_action( 'admin_enqueue_scripts', 'wpmf_load_custom_wp_admin_script' );
  $is_acf_admin_page = ( ! empty($typenow) && $typenow === 'acf-field-group' );
  
  if ($wp_media_folder_is_hooked  && $is_acf_admin_page ) {
    global $wp_scripts;

    // Make sure the handle is actually registered and has an src.
    // The handle 'script' is used by WP Media Folder (1.0.4).
    if ( isset( $wp_scripts->registered[ 'script' ]->src ) ) {
      $script_src = $wp_scripts->registered[ 'script' ]->src;
      // We should only dequeue the script if it seems to be belonging to WP Media Folder.
      // These checks are made to prevent any errors if WP Media Folder actually changes 
      // their handle for the script when registering it.
      if ( strpos( $script_src, 'wp-media-folder/script.js' ) !== false ) {
        wp_dequeue_script( 'script' );
      }        
    }
  }
}
add_action( 'admin_enqueue_scripts', 'hampusn_admin_enqueue_scripts', 999 ); // 999 might be a bit overkill...