using hook_form_alter() to change year range of datetime select widget, with deltas for multi-value fields

Question

I have multiple date fields on a node form for which I am using the select widget. The year select list has a range of years that is far too wide for our purposes (1900-present), so we want to limit it. I am able to accomplish this with hook_form_alter, however the fields that are multi-value to not reflect this change when they are loaded with ajax. Here is my current code which gets the first deltas:

public function alterQuarterlyReportForm(&$form, FormState  $form_state, $form_id) {

// form_alter functionality for quarterly reports
if ($form_id == 'node_quarterly_report_form' || $form_id == 'node_quarterly_report_edit_form') {

  // Limiting range of years in date fields on report form
      $form['field_draft_evaluation_date']['widget'][0]['value']['#date_year_range'] = '-3:+3';
      $form['field_draft_protocol_date']['widget'][0]['value']['#date_year_range'] = '-3:+3';
      $form['field_updated_milestone_plandate']['widget'][0]['value']['#date_year_range'] = '-3:+3';
      $form['field_committee_date']['widget'][0]['value']['#date_year_range'] = '-3:+3';
      $form['field_liaison_meeting_dates']['widget'][0]['value']['#date_year_range'] = '-3:+3';
      $form['field_meeting_date']['widget'][0]['value']['#date_year_range'] = '-3:+3'; }}

Obviously these are each set for delta 0, and what I am having trouble figuring out is how to get this working for each additional value that a user wants to enter. I have attempted a few foreach() loops, but I am not getting it right.

Answer 1

I think you probably want this:

$fields = [
  'field_draft_evaluation_date',
  'field_draft_protocol_date',
  'field_updated_milestone_plandate',
  'field_committee_date',
  'field_liaison_meeting_dates',
  'field_meeting_date',
];

foreach ($fields as $field) {
  foreach (\Drupal\Core\Render\Element::children($form[$field]) as $index) {
    $form[$field]['widget'][$index]['value']['#date_year_range'] = '-3:+3';
  }
}

Note that Element::children() returns "The children of an element array are those key/value pairs whose key does not start with a '#'". For the above code, it will return the deltas for multi-value fields.