added orcid field formatter

src/Plugin/Field/FieldFormatter/OrcidFieldFormatter.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace Drupal\doi_field_formatter\Plugin\Field\FieldFormatter;
+
+use Drupal\Core\Field\FormatterBase;
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Url;
+use Drupal\Core\Link;
+
+
+/**
+ * Plugin implementation of the 'Facet_Field_Formatter' formatter.
+ *
+ * @FieldFormatter(
+ *   id = "orcid_text_field_formatter",
+ *   module = "doi_field_formatter",
+ *   label = @Translation("Orcid Field Formatter"),
+ *   description = @Translation("Create links to ORCID resources"),
+ *   field_types = {
+ *     "text",
+ *     "string"
+ *   }
+ * )
+ */
+class OrcidFieldFormatter extends FormatterBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsSummary() {
+    $summary = [];
+    $summary[] = $this->t('Format string or text fields as as ORCID links.');
+    return $summary;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function viewElements(FieldItemListInterface $items, $langcode) {
+    $element = [];
+    foreach ($items as $delta => $item) {
+      $prefix = 'https://orcid.org/';
+      // Assumes all field values are just plain text or strings values and not full orcid URLS.
+      $orcidUrl = $prefix . $item->value;
+      $imgSrc = '<img class="orcid-id " src="https://orcid.org/sites/default/files/images/orcid_24x24.png">';
+      $link = Link::fromTextAndUrl($orcidUrl, Url::fromUri($orcidUrl));
+      $element[$delta] = [$link->toRenderable()];
+      $element[$delta][0]['#prefix'] = $imgSrc;
+    }
+    return $element;
+  }
+}