Merge pull request #26 from FranMoraton/obtainFirstItem

Obtain collection first item
PcComponentes · May 26, 2021 · 3b33b54 · 3b33b54
2 parents f2bbe03 + c0413d4
commit 3b33b54
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Showing 3 changed files with 51 additions and 1 deletion.
diff --git a/src/Domain/Model/ValueObject/CollectionValueObject.php b/src/Domain/Model/ValueObject/CollectionValueObject.php
@@ -54,7 +54,7 @@ public function filter(callable $func)
 
     public function map(callable $func): CollectionValueObject
     {
-        return new self(\array_map($func, $this->items));
+        return new static(\array_map($func, $this->items));
     }
 
     public function reduce(callable $func, $initial)
@@ -104,4 +104,9 @@ protected function removeItem($item): self
             static fn ($current) => $current !== $item,
         );
     }
+
+    public function first()
+    {
+        return $this->items[array_key_first($this->items)] ?? null;
+    }
 }
diff --git a/tests/Domain/Model/ValueObject/CollectionValueObjectTest.php b/tests/Domain/Model/ValueObject/CollectionValueObjectTest.php
@@ -157,4 +157,44 @@ public function given_collection_when_ask_to_remove_item_then_return_new_collect
         $this->assertEquals([1, 2, 3, 4], $collection->jsonSerialize());
         $this->assertEquals([1, 2, 4], $newCollection->jsonSerialize());
     }
+
+    /**
+     * @test
+     */
+    public function given_an_empty_collection_when_ask_to_obtain_first_item_then_return_null()
+    {
+        $collection = CollectionValueObjectTested::from([]);
+        $item = $collection->firstItem();
+
+        $this->assertEquals(null, $item);
+    }
+
+    /**
+     * @test
+     */
+    public function given_a_hash_map_collection_when_ask_to_obtain_first_item_then_return_first_item()
+    {
+        $firstItem = 1;
+        $collection = CollectionValueObjectTested::from(['a' => $firstItem, 'b' => 2, 'c' => 3, 'd' => 4]);
+        $item = $collection->firstItem();
+
+        $this->assertEquals(['a' => $firstItem, 'b' => 2, 'c' => 3, 'd' => 4], $collection->jsonSerialize());
+        $this->assertEquals($firstItem, $item);
+    }
+
+    /**
+     * @test
+     */
+    public function given_a_collection_when_ask_to_obtain_first_item_then_return_first_item()
+    {
+        $firstItem = 1;
+        $collection = CollectionValueObjectTested::from([$firstItem, 2, 3, 4]);
+        $item = $collection->firstItem();
+
+        $this->assertEquals([$firstItem, 2, 3, 4], $collection->jsonSerialize());
+        $this->assertEquals($firstItem, $item);
+        $this->assertNotEquals(2, $item);
+        $this->assertNotEquals(3, $item);
+        $this->assertNotEquals(4, $item);
+    }
 }
diff --git a/tests/Domain/Model/ValueObject/CollectionValueObjectTested.php b/tests/Domain/Model/ValueObject/CollectionValueObjectTested.php
@@ -16,4 +16,9 @@ public function remove($item)
     {
         return $this->removeItem($item);
     }
+
+    public function firstItem()
+    {
+        return $this->first();
+    }
 }