Higher order tap.

This allows you to pass a single argument into tap, then call any
method on that object, and return the object itself. I’ve found this
primarily useful around Eloquent methods that I want to return $this….
For example: return tap($model)->update([‘foo’ => ‘bar’]);

src/Illuminate/Support/HigherOrderTapProxy.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Illuminate\Support;
+
+class HigherOrderTapProxy
+{
+    /**
+     * The target being tapped.
+     *
+     * @var mixed
+     */
+    public $target;
+
+    /**
+     * Create a new tap proxy instance.
+     *
+     * @param  mixed  $target
+     * @return void
+     */
+    public function __construct($target)
+    {
+        $this->target = $target;
+    }
+
+    /**
+     * Dynamically pass method calls to the target.
+     *
+     * @param  string  $method
+     * @param  array  $parameters
+     * @return mixed
+     */
+    public function __call($method, $parameters)
+    {
+        $this->target->{$method}(...$parameters);
+
+        return $this->target;
+    }
+}

src/Illuminate/Support/helpers.php

@@ -5,6 +5,7 @@
 use Illuminate\Support\Collection;
 use Illuminate\Support\Debug\Dumper;
 use Illuminate\Contracts\Support\Htmlable;
+use Illuminate\Support\HigherOrderTapProxy;
 
 if (! function_exists('append_config')) {
     /**
@@ -870,11 +871,15 @@ function studly_case($value)
      * Call the given Closure with the given value then return the value.
      *
      * @param  mixed  $value
-     * @param  callable  $callback
+     * @param  callable|null  $callback
      * @return mixed
      */
-    function tap($value, $callback)
+    function tap($value, $callback = null)
     {
+        if (is_null($callback)) {
+            return new HigherOrderTapProxy($value);
+        }
+
         $callback($value);
 
         return $value;

tests/Support/SupportHelpersTest.php

@@ -705,6 +705,10 @@ public function testTap()
         $this->assertEquals(2, tap($object, function ($object) {
             $object->id = 2;
         })->id);
+
+        $mock = m::mock();
+        $mock->shouldReceive('foo')->once()->andReturn('bar');
+        $this->assertEquals($mock, tap($mock)->foo());
     }
 }