add nova

nova/src/Fields/Expandable.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace Laravel\Nova\Fields;
+
+trait Expandable
+{
+    /**
+     * The callback to be used to determine whether the field should be expanded.
+     *
+     * @var (callable():(bool))|null
+     */
+    public $expandableCallback;
+
+    /**
+     * Whether to always show the content for the field expanded or not.
+     *
+     * @var bool
+     */
+    public $alwaysShow = false;
+
+    /**
+     * Always show the content of textarea fields inside Nova.
+     *
+     * @return $this
+     */
+    public function alwaysShow()
+    {
+        $this->alwaysShow = true;
+
+        return $this;
+    }
+
+    /**
+     * Define the callback that should be used to determine whether the field should be collapsed.
+     *
+     * @param  callable():bool  $expandableCallback
+     * @return $this
+     */
+    public function shouldShow(callable $expandableCallback)
+    {
+        $this->expandableCallback = $expandableCallback;
+
+        return $this;
+    }
+
+    /**
+     * Determine whether the field should be expanded.
+     *
+     * @return bool
+     */
+    public function shouldBeExpanded()
+    {
+        if ($this->alwaysShow) {
+            return true;
+        }
+
+        return isset($this->expandableCallback)
+                        ? call_user_func($this->expandableCallback)
+                        : false;
+    }
+}