How to check if an entity bundle has a field?
Woops, this is closely related to Get all fields defined in a bundle, but since that gets all fields, I'll post this.

Use the EntityFieldManager (entity_field.manager) service, specifically the getFieldDefinitions method, to get all field definitions, and then check for your specific field.

function doesBundleHaveField($entity_type = 'node', $bundle = 'page', $field_name = 'field_paragraphs') {
  $all_bundle_fields = \Drupal::service('entity_field.manager')-&gt;getFieldDefinitions($entity_type, $bundle);
  return isset($all_bundle_fields[$field_name]);
}