EntityViewBuilder::viewFieldItem

public EntityViewBuilder::viewFieldItem(FieldItemInterface $item, $display = array())

public function viewFieldItem(FieldItemInterface $item, $display = array()) {
  $entity = $item->getEntity();
  $field_name = $item->getFieldDefinition()->getName();

  // Clone the entity since we are going to modify field values.
  $clone = clone $entity;

  // Push the item as the single value for the field, and defer to viewField()
  // to build the render array for the whole list.
  $clone->{$field_name}->setValue(array($item->getValue()));
  $elements = $this->viewField($clone->{$field_name}, $display);

  // Extract the part of the render array we need.
  $output = isset($elements[0]) ? $elements[0] : array();
  if (isset($elements['#access'])) {
    $output['#access'] = $elements['#access'];
  }

  return $output;
}