Add array_set and Arr::set functionality

src/Arr.php

@@ -64,4 +64,34 @@ public static function has(array $array, $key)
 
         return true;
     }
+
+    /**
+     * Set an array item to a given value using "dot" notation.
+     *
+     * @param  array   $array
+     * @param  string  $key
+     * @param  mixed   $value
+     * @return array
+     */
+    public static function set(&$array, $key, $value)
+    {
+        $keys = explode('.', $key);
+
+        while (count($keys) > 1) {
+            $key = array_shift($keys);
+
+            // If the key doesn't exist at this depth, we will just create an empty array
+            // to hold the next value, allowing us to create the arrays to hold final
+            // values at the correct depth. Then we'll keep digging into the array.
+            if (! isset($array[$key]) || ! is_array($array[$key])) {
+                $array[$key] = [];
+            }
+
+            $array = &$array[$key];
+        }
+
+        $array[array_shift($keys)] = $value;
+
+        return $array;
+    }
 }

src/array-helpers.php

@@ -11,3 +11,8 @@ function array_has($array, $key)
 {
     return Arr::has($array, $key);
 }
+
+function array_set(&$array, $key, $value)
+{
+    return Arr::set($array, $key, $value);
+}

tests/ArraySetTest.php

@@ -0,0 +1,82 @@
+<?php
+
+namespace ArrayHelpers;
+
+use PHPUnit\Framework\TestCase;
+
+class ArraySetTest extends TestCase
+{
+    public function testWillSetSingleValue()
+    {
+        $expected = ['rolling' => 'stones'];
+
+        $initial = [];
+        Arr::set($initial, 'rolling', 'stones');
+        $this->assertEquals($expected, $initial);
+
+        $initial = [];
+        array_set($initial, 'rolling', 'stones');
+        $this->assertEquals($expected, $initial);
+    }
+
+    public function testWillOverwriteExistingValue()
+    {
+        $initial = ['rolling' => 'stones'];
+        Arr::set($initial, 'rolling', 'thunder');
+        $this->assertEquals(
+            ['rolling' => 'thunder'],
+            $initial
+        );
+    }
+
+    public function testWillSetUsingDotNotation()
+    {
+        $initial = [];
+        Arr::set($initial, "i.can't.get.no", 'satisfaction');
+        $this->assertEquals(
+            [
+                'i' => [
+                    "can't" => [
+                        'get' => [
+                            'no' => 'satisfaction',
+                        ],
+                    ],
+                ],
+            ],
+            $initial
+        );
+    }
+
+    public function testWillOnlyPartiallyOverwriteUsingDotNotation()
+    {
+        $initial = [
+            'i' => [
+                "can't" => [
+                    'live' => [
+                        'in' => [
+                            'a' => 'living room',
+                        ]
+                    ]
+                ]
+            ]
+        ];
+        Arr::set($initial, "i.can't.get.no", 'satisfaction');
+        $this->assertEquals(
+            [
+                'i' => [
+                    "can't" => [
+                        'live' => [
+                            'in' => [
+                                'a' => 'living room',
+                            ],
+                        ],
+                        'get' => [
+                            'no' => 'satisfaction',
+                        ],
+                    ],
+                ],
+            ],
+            $initial
+        );
+    }
+}