How to conditionally not load js for anonymous users?

Question

We have a situation where our contrib modules are being loaded for the anonymous user, but they are not needed. As a result, we are seeing higher page load times. We tried using hook_js_alter in a custom module with the code below. What is the proper way to not load the js files we don't need for the anonymous user?

mymodule_js_alter($javascript) {

  $javascript['somefile']['weight']=50;
  $javascript['somefile']['scope']=bottom; //region for bottom of the page

}

Current code:

function mymodule_js_alter(&$javascript) {

    if(user_is_anonymous()){ 
       unset($javascript['sites/all/modules/contrib/autocomplete/autocomplete.js']); 
     } 
 }

Answer 1

If you don't want to load your JS in anonymous user, check the user if its logged in then load the JS file if its true. use user_is_logged_in() to check if user is logged in, place it inside your hook_preprocess_page().

Example:

  $theme_path = drupal_get_path('theme', 'zen');
  // This will load only in authenticated user.
  if(user_is_logged_in()) {
    drupal_add_js($theme_path . '/plugins/jQuery/jquery-2.2.3.min.js');
  }

Answer 2

You can use it like:

/**
 * Implements hook_js_alter().
*/
function hook_js_alter(&$javascript) {
// Removes the js for anonymous users.
  if(user_is_anonymous()) {  
    unset($javascript['sites/all/theme/js/file.js']);
  }        
}