Add Function.bindKey function

pierredup · pierredup · commit 36ac97dddd37 · 2018-12-10T23:41:44.000+02:00
diff --git a/src/Function/bindKey.php b/src/Function/bindKey.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+namespace _;
+
+/**
+ * Creates a function that invokes the method `$function` of `$object` with `$partials`
+ * prepended to the arguments it receives.
+ *
+ * This method differs from `bind` by allowing bound functions to reference
+ * methods that may be redefined or don't yet exist
+ *
+ * @category Function
+ *
+ * @param object|mixed $object   The object to invoke the method on.
+ * @param string       $function The name of the method.
+ * @param mixed[]      $partials The arguments to be partially applied.
+ *
+ * @return callable Returns the new bound function.
+ * @example
+ *
+ * $object = new class {
+ *     private $user = 'fred';
+ *     function greet($greeting, $punctuation) {
+ *         return $greeting.' '.$this->user.$punctuation;
+ *     }
+ * };
+ *
+ * $bound = bindKey($object, 'greet', 'hi');
+ * $bound('!');
+ * // => 'hi fred!'
+ */
+function bindKey($object, string $function, ...$partials): callable
+{
+    return function (...$args) use ($object, $function, $partials) {
+        $function = \Closure::fromCallable([$object, $function])->bindTo($object, get_class($object));
+
+        return $function(...array_merge($partials, $args));
+    };
+}
diff --git a/tests/Function/BindKeyTest.php b/tests/Function/BindKeyTest.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the SolidWorx Lodash-PHP project.
+ *
+ * @author     Pierre du Plessis <open-source@solidworx.co>
+ * @copyright  Copyright (c) 2017
+ */
+
+use PHPUnit\Framework\TestCase;
+use function _\bindKey;
+
+class BindKeyTest extends TestCase
+{
+    public function testBindKey()
+    {
+        $object = new class
+        {
+            private $user = 'fred';
+
+            function greet($greeting, $punctuation)
+            {
+                return $greeting.' '.$this->user.$punctuation;
+            }
+        };
+
+        $bound = bindKey($object, 'greet', 'hi');
+
+        $this->assertSame('hi fred!', $bound('!'));
+    }
+}
