Arrays::first() & last(): added parameter $predicate [Closes #305]

thx @into-the-v0id

src/Utils/Arrays.php

@@ -121,26 +121,46 @@ public static function contains(array $array, mixed $value): bool
 
 
 	/**
-	 * Returns the first item from the array or null if array is empty.
+	 * Returns the first item from the array (matching the specified predicate if given) or null if there is no such item.
 	 * @template T
 	 * @param  array<T>  $array
 	 * @return ?T
 	 */
-	public static function first(array $array): mixed
+	public static function first(array $array, ?callable $predicate = null): mixed
 	{
-		return $array[array_key_first($array)] ?? null;
+		$key = $predicate
+			? self::firstKey($array, $predicate)
+			: array_key_first($array);
+		return $key === null ? null : $array[$key];
 	}
 
 
 	/**
-	 * Returns the last item from the array or null if array is empty.
+	 * Returns the last item from the array (matching the specified predicate if given) or null if there is no such item.
 	 * @template T
 	 * @param  array<T>  $array
 	 * @return ?T
 	 */
-	public static function last(array $array): mixed
+	public static function last(array $array, ?callable $predicate = null): mixed
 	{
-		return $array[array_key_last($array)] ?? null;
+		$key = $predicate
+			? self::firstKey(array_reverse($array, preserve_keys: true), $predicate)
+			: array_key_last($array);
+		return $key === null ? null : $array[$key];
+	}
+
+
+	/**
+	 * Returns the key of first item (matching the specified predicate if given) or null if there is no such item.
+	 */
+	private static function firstKey(array $array, callable $predicate): int|string|null
+	{
+		foreach ($array as $k => $v) {
+			if ($predicate($v, $k, $array)) {
+				return $k;
+			}
+		}
+		return null;
 	}
 
 

tests/Utils/Arrays.first().phpt

@@ -9,13 +9,32 @@ use Tester\Assert;
 require __DIR__ . '/../bootstrap.php';
 
 
-Assert::null(Arrays::first([]));
-Assert::null(Arrays::first([null]));
-Assert::false(Arrays::first([false]));
-Assert::same(1, Arrays::first([1, 2, 3]));
-
-
-$arr = [1, 2, 3];
-end($arr);
-Assert::same(1, Arrays::first($arr));
-Assert::same(3, current($arr));
+test('no predicate', function () {
+	Assert::null(Arrays::first([]));
+	Assert::null(Arrays::first([null]));
+	Assert::false(Arrays::first([false]));
+	Assert::same(1, Arrays::first([1, 2, 3]));
+});
+
+test('internal array pointer is not affected', function () {
+	$arr = [1, 2, 3];
+	end($arr);
+	Assert::same(1, Arrays::first($arr));
+	Assert::same(3, current($arr));
+});
+
+test('with predicate', function () {
+	Assert::null(Arrays::first([], fn() => true));
+	Assert::null(Arrays::first([], fn() => false));
+	Assert::null(Arrays::first(['' => 'x'], fn() => false));
+	Assert::null(Arrays::first([null], fn() => true));
+	Assert::null(Arrays::first([null], fn() => false));
+	Assert::same(1, Arrays::first([1, 2, 3], fn() => true));
+	Assert::null(Arrays::first([1, 2, 3], fn() => false));
+	Assert::same(3, Arrays::first([1, 2, 3], fn($v) => $v > 2));
+	Assert::same(1, Arrays::first([1, 2, 3], fn($v) => $v < 2));
+});
+
+test('predicate arguments', function () {
+	Arrays::first([2 => 'x'], fn() => Assert::same(['x', 2, [2 => 'x']], func_get_args()));
+});

tests/Utils/Arrays.last().phpt

@@ -9,12 +9,31 @@ use Tester\Assert;
 require __DIR__ . '/../bootstrap.php';
 
 
-Assert::null(Arrays::last([]));
-Assert::null(Arrays::last([null]));
-Assert::false(Arrays::last([false]));
-Assert::same(3, Arrays::last([1, 2, 3]));
-
-
-$arr = [1, 2, 3];
-Assert::same(3, Arrays::last($arr));
-Assert::same(1, current($arr));
+test('no predicate', function () {
+	Assert::null(Arrays::last([]));
+	Assert::null(Arrays::last([null]));
+	Assert::false(Arrays::last([false]));
+	Assert::same(3, Arrays::last([1, 2, 3]));
+});
+
+test('internal array pointer is not affected', function () {
+	$arr = [1, 2, 3];
+	Assert::same(3, Arrays::last($arr));
+	Assert::same(1, current($arr));
+});
+
+test('with predicate', function () {
+	Assert::null(Arrays::last([], fn() => true));
+	Assert::null(Arrays::last([], fn() => false));
+	Assert::null(Arrays::last(['' => 'x'], fn() => false));
+	Assert::null(Arrays::last([null], fn() => true));
+	Assert::null(Arrays::last([null], fn() => false));
+	Assert::same(3, Arrays::last([1, 2, 3], fn() => true));
+	Assert::null(Arrays::last([1, 2, 3], fn() => false));
+	Assert::same(3, Arrays::last([1, 2, 3], fn($v) => $v > 2));
+	Assert::same(1, Arrays::last([1, 2, 3], fn($v) => $v < 2));
+});
+
+test('predicate arguments', function () {
+	Arrays::last([2 => 'x'], fn() => Assert::same(['x', 2, [2 => 'x']], func_get_args()));
+});