Arrays: added updateDiff()

src/Utils/Arrays.php

@@ -343,4 +343,19 @@ public static function toKey($value)
 	{
 		return key([$value => null]);
 	}
+
+
+	/**
+	 * Returns items required to synchronize associative array $from to array $to.
+	 */
+	public static function updateDiff(array $from, array $to): array
+	{
+		$diff = [];
+		foreach ($to as $k => $v) {
+			if (!array_key_exists($k, $from) || $v !== $from[$k]) {
+				$diff[$k] = $v;
+			}
+		}
+		return $diff;
+	}
 }

tests/Utils/Arrays.updateDiff().phpt

@@ -0,0 +1,71 @@
+<?php
+
+/**
+ * Test: Nette\Utils\Arrays::updateDiff()
+ */
+
+declare(strict_types=1);
+
+use Nette\Utils\Arrays;
+use Tester\Assert;
+
+
+require __DIR__ . '/../bootstrap.php';
+
+
+test('Basics', function () {
+	Assert::same([], Arrays::updateDiff([], []));
+	Assert::same([], Arrays::updateDiff(['a' => ''], []));
+});
+
+
+test('New keys', function () {
+	$to = [
+		'a' => null,
+		'b' => false,
+		'c' => '',
+		'd' => 0,
+	];
+	Assert::same($to, Arrays::updateDiff([], $to));
+});
+
+
+test('To falsy values', function () {
+	$from = [
+		'a' => null,
+		'b' => false,
+		'c' => '',
+		'd' => 0,
+	];
+
+	$toNull = ['a' => null, 'b' => null, 'c' => null, 'd' => null];
+	Assert::same([
+		'b' => null,
+		'c' => null,
+		'd' => null,
+	], Arrays::updateDiff($from, $toNull));
+
+
+	$toFalse = ['a' => false, 'b' => false, 'c' => false, 'd' => false];
+	Assert::same([
+		'a' => false,
+		'c' => false,
+		'd' => false,
+	], Arrays::updateDiff($from, $toFalse));
+
+
+	$toEmpty = ['a' => '', 'b' => '', 'c' => '', 'd' => ''];
+	Assert::same([
+		'a' => '',
+		'b' => '',
+		'd' => '',
+	], Arrays::updateDiff($from, $toEmpty));
+
+
+	$toZero = ['a' => 0, 'b' => 0, 'c' => 0, 'd' => 0];
+	Assert::same([
+		'a' => 0,
+		'b' => 0,
+		'c' => 0,
+	], Arrays::updateDiff($from, $toZero));
+});