introduce Option::fromNullable() and ->toNullable()

Author: someniatko

src/Option.php

@@ -23,14 +23,26 @@ public static function some($value): Some
         return new Some($value);
     }
 
-    /**y
+    /**
      * @return None
      */
     public static function none(): None
     {
         return self::$none ??= new None();
     }
 
+    /**
+     * @template TNew
+     * @param TNew|null $value
+     * @return Option<TNew>
+     */
+    public static function fromNullable($value): Option
+    {
+        return $value === null
+            ? self::none()
+            : self::some($value);
+    }
+
     /**
      * @template T
      * @param list<Option<T>> $options
@@ -124,4 +136,12 @@ public function toResultLazy(callable $else): ResultInterface
             ->map(fn($t) => new Success($t))
             ->getOr(fn() => new Error($else()));
     }
+
+    /**
+     * @return TValue|null
+     */
+    public function toNullable()
+    {
+        return $this->getOrElse(null);
+    }
 }

test/OptionTest.php

@@ -94,4 +94,34 @@ public function testGetOrThrowNone(): void
         /** @psalm-suppress UnusedMethodCall */
         $option->getOrThrow(new \RuntimeException('expected'));
     }
+
+    public function testFromNullableGivenValue(): void
+    {
+        $option = Option::fromNullable(123);
+        $mapped = $option->map(fn(int $val) => $val + 1);
+        self::assertEquals(124, $mapped->getOrElse(-1));
+    }
+
+    public function testFromNullableGivenNull(): void
+    {
+        /** @var Option<int> $option */
+        $option = Option::fromNullable(null);
+        $mapped = $option->map(fn(int $val) => $val + 1);
+        self::assertEquals(-1, $mapped->getOrElse(-1));
+    }
+
+    public function testToNullableSome(): void
+    {
+        $option = Option::some(123);
+        $nullable = $option->toNullable();
+        self::assertEquals(123, $nullable);
+    }
+
+    public function testToNullableNone(): void
+    {
+        /** @var Option<int> $option */
+        $option = Option::none();
+        $nullable = $option->toNullable();
+        self::assertNull($nullable);
+    }
 }