Clarify difference between hook_form_TYPE_alter and hook_form_TYPE_EDIT_alter

Question

I have a site with a lot of hook form alters for node forms and I'm finding that I have to create two separate hook functions to affect both the node create and node edit forms.

For example, I have to put both:

module_events_form_node_event_form_alter()

and

module_events_form_node_event_edit_form_alter()

With the same functionality in both functions so that it covers both new and edited nodes. Is there a way to have one hook_form_alter() to cover both form conditions?

Answer 1

You can either use the full form ID with content type and operation or the base form ID node_form. This is without the operation but also missing the content type. So when you alter the base form you have to check for a specific content type if you don't want to alter all node forms:

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function mymodule_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $node = $form_state->getFormObject()->getEntity();
  if ($node->getType() == 'event') {
    // change the node form for the content type event and any operation
  }
}