feat: Add default value for with() (#194)

phanan · lstrojny · commit 7aadb259b13c · 2019-12-09T11:22:02.000+01:00
diff --git a/docs/functional-php.md b/docs/functional-php.md
@@ -500,7 +500,9 @@ Functional PHP comes with a set of invocation helpers that ease calling function
 
 
 ## with()
-Invoke a callback on a value if the value is not null
+Invoke a callback on a value if the value is not null.
+
+``Function\with(mixed $value, callable $callback, bool $invokeValue = true, mixed $default = null): mixed``
 
 ```php
 <?php
@@ -516,6 +518,8 @@ $retval = with($value, function($value) {
 `with()` returns whatever the callback returns. In the above example
 `$retval` would be `'my_result'`.
 
+If the value of `$value` is `null`, `with()` will return `$default` which defaults to be `null`.
+
 ## invoke_if()
 
 ``mixed Functional\invoke_if(mixed $object, string $methodName[, array $methodArguments, mixed $defaultValue])``
diff --git a/src/Functional/With.php b/src/Functional/With.php
@@ -18,14 +18,15 @@
  * @param mixed $value
  * @param callable $callback
  * @param bool $invokeValue Set to false to not invoke $value if it is a callable. Will be removed in 2.0
+ * @param mixed $default The default value to return if $value is null
  * @return mixed
  */
-function with($value, callable $callback, $invokeValue = true)
+function with($value, callable $callback, $invokeValue = true, $default = null)
 {
     InvalidArgumentException::assertCallback($callback, __FUNCTION__, 2);
 
     if ($value === null) {
-        return null;
+        return $default;
     }
 
     if ($invokeValue && \is_callable($value)) {
diff --git a/tests/Functional/WithTest.php b/tests/Functional/WithTest.php
@@ -62,4 +62,18 @@ public function testPassNonCallable()
         $this->expectArgumentError("Argument 2 passed to Functional\with() must be callable");
         with(null, 'undefinedFunction');
     }
+
+    public function testDefaultValue()
+    {
+        $this->assertSame(
+            'foo',
+            with(
+                null,
+                function () {
+                },
+                true,
+                'foo'
+            )
+        );
+    }
 }
