--- /dev/null
+<?php
+
+namespace Drupal\migrate_plus\Plugin\migrate\process;
+
+use Drupal\migrate\MigrateException;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\Row;
+
+/**
+ * Performs an array_shift() on a source array.
+ *
+ * @MigrateProcessPlugin(
+ * id = "array_shift",
+ * handle_multiples = TRUE
+ * )
+ *
+ * The "extract" plugin in core can extract array values when indexes are
+ * already known. This plugin helps extract the first value in an array by
+ * performing a "shift" operation.
+ *
+ * Example: Say, the migration source has an associative array of names in
+ * a property called "authors" and the keys in the array can vary, you
+ * can extract the first value like this:
+ *
+ * @code
+ * first_author:
+ * plugin: array_shift
+ * source: authors
+ * @endcode
+ */
+class ArrayShift extends ProcessPluginBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+ if (!is_array($value)) {
+ throw new MigrateException('Input should be an array.');
+ }
+ return array_shift($value);
+ }
+
+}