How can I add an external/third party library with type = 'module' using drupal_add_js()?

  drupal_add_js('path_to_external_JS_file_on_CDN', [
    'every_page' => TRUE,
    'type' => 'external',
    'defer' => 'defer',
    'attributes' => [
      'async' => true,
      'type' => 'module'
    ],
  ]
);

I tried all combinations of the above, but I couldn't get it work. Is there a way to achieve it using drupal_add_js(), or should I use some other way?

I am trying to achieve this.

<script type='module' src='path_to_external_JS_file_on_CDN'></script>

Edit: I added the code above in my_module_preprocess_page(&$variables). The following code works as expected.

drupal_add_js('path_to_external_JS_file_on_CDN', [
  'every_page' => TRUE,
  'type' => 'external'
]);

I just can't figure out how to load a JavaScript file with the type='module' attribute.

According the function's documentation the module is not an allowed type, that's why it doesn't work.

You may try omitting the type or use the default one - file instead.

The allowed types are 'file', 'inline', 'external' or 'setting'.

The hook you tried my_module_preprocess_page(&$variables) is a good choice.

You may also use the hook_init YOUR_MODULE_NAME_init() in a custom module to ensure your library is loaded everywhere. Please note that hook_init() is triggered after the theme and all modules are loaded already in the memory.

Please check if this solves your issue and put a note with the result.