tripal/tripal_chado/includes/TripalFields/uo__unit/uo__unit_formatter.inc

<?php

class uo__unit_formatter extends ChadoFieldFormatter {

  // The default label for this field.
  public static $default_label = 'Unit';

  // The list of field types for which this formatter is appropriate.
  public static $field_types = ['uo__unit'];

  /**
   * @see TripalFieldFormatter::view()
   */
  public function view(&$element, $entity_type, $entity, $langcode, $items, $display) {
    $content = '';
    if ($items[0]['value']) {
      $content = $items[0]['value'];
    }
    $element[0] = [
      // We create a render array to produce the desired markup,
      '#type' => 'markup',
      '#markup' => $content,
    ];
  }
}