add nova

nova/src/Fields/AttachableRelation.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace Laravel\Nova\Fields;
+
+use Laravel\Nova\Http\Requests\NovaRequest;
+
+trait AttachableRelation
+{
+    /**
+     * Determines if the display values should be automatically sorted.
+     *
+     * @var (callable(\Laravel\Nova\Http\Requests\NovaRequest):(bool))|bool
+     */
+    public $reordersOnAttachableCallback = true;
+
+    /**
+     * Determine if the display values should be automatically sorted when rendering attachable relation.
+     *
+     * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
+     * @return bool
+     */
+    public function shouldReorderAttachableValues(NovaRequest $request)
+    {
+        if (is_callable($this->reordersOnAttachableCallback)) {
+            return call_user_func($this->reordersOnAttachableCallback, $request);
+        }
+
+        return $this->reordersOnAttachableCallback;
+    }
+
+    /**
+     * Determine reordering on attachables.
+     *
+     * @return $this
+     */
+    public function dontReorderAttachables()
+    {
+        $this->reordersOnAttachableCallback = false;
+
+        return $this;
+    }
+
+    /**
+     * Determine reordering on attachables.
+     *
+     * @param  (callable(\Laravel\Nova\Http\Requests\NovaRequest):(bool))|bool  $value
+     * @return $this
+     */
+    public function reorderAttachables($value = true)
+    {
+        $this->reordersOnAttachableCallback = $value;
+
+        return $this;
+    }
+}