Enhancement: Implement ChainNormalizer

README.md

@@ -20,6 +20,7 @@ $ composer require localheinz/json-normalizer
 This package comes with the following normalizers:
 
 * [`Localheinz\Json\Normalizer\CallableNormalizer`](#callablenormalizer)
+* [`Localheinz\Json\Normalizer\ChainNormalizer`](#chainnormalizer)
 * [`Localheinz\Json\Normalizer\FinalNewLineNormalizer`](#finalnewlinenormalizer)
 * [`Localheinz\Json\Normalizer\IndentNormalizer`](#indentnormalizer)
 * [`Localheinz\Json\Normalizer\JsonEncodeNormalizer`](#jsonencodenormalizer)
@@ -62,6 +63,33 @@ $normalized = $normalizer->normalize($json);
 
 The normalized version will now have the callable applied to it.
 
+### `ChainNormalizer`
+
+If you want to apply multiple normalizers in a chain, you can use the `ChainNormalizer`.
+
+```php
+use Localheinz\Json\Normalizer;
+
+$json = <<<'JSON'
+{
+    "name": "Andreas Möller",
+    "url": "https://localheinz.com"
+}
+JSON;
+
+$normalizer = new Normalizer\ChainNormalizer(
+    new Normalizer\JsonEncodeNormalizer(JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES),
+    new Normalizer\IndentNormalizer('  '),
+    new Normalizer\FinalNewLineNormalizer()
+);
+
+$normalized = $normalizer->normalize($json);
+```
+
+The normalized version will now contain the result of applying all normalizers in a chain, one after another.
+
+:bulb: Be careful with the order of the normalizers, as one normalizer might override changes a previous normalizer applied.
+
 ### `FinalNewLineNormalizer`
 
 If you want to ensure that a JSON file has a single final new line, you can use the `FinalNewLineNormalizer`.

src/ChainNormalizer.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2018 Andreas Möller.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * @see https://github.com/localheinz/json-normalizer
+ */
+
+namespace Localheinz\Json\Normalizer;
+
+final class ChainNormalizer implements NormalizerInterface
+{
+    /**
+     * @var NormalizerInterface[]
+     */
+    private $normalizers;
+
+    public function __construct(NormalizerInterface ...$normalizers)
+    {
+        $this->normalizers = $normalizers;
+    }
+
+    public function normalize(string $json): string
+    {
+        if (null === \json_decode($json) && JSON_ERROR_NONE !== \json_last_error()) {
+            throw new \InvalidArgumentException(\sprintf(
+                '"%s" is not valid JSON.',
+                $json
+            ));
+        }
+
+        foreach ($this->normalizers as $normalizer) {
+            $json = $normalizer->normalize($json);
+        }
+
+        return $json;
+    }
+}

test/Unit/ChainNormalizerTest.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2018 Andreas Möller.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * @see https://github.com/localheinz/json-normalizer
+ */
+
+namespace Localheinz\Json\Normalizer\Test\Unit;
+
+use Localheinz\Json\Normalizer\ChainNormalizer;
+use Localheinz\Json\Normalizer\NormalizerInterface;
+use Prophecy\Argument;
+
+final class ChainNormalizerTest extends AbstractNormalizerTestCase
+{
+    public function testNormalizePassesJsonThroughNormalizers()
+    {
+        $count = $this->faker()->numberBetween(3, 5);
+
+        $json = <<<'JSON'
+{
+    "name": "Andreas Möller",
+    "url": "https://localheinz.com",
+    "normalized-by": "%s"
+}
+JSON;
+
+        $normalize = function (string $json, int $index) {
+            return \sprintf(
+                $json,
+                $index
+            );
+        };
+
+        $normalized = $normalize(
+            $json,
+            $count - 1
+        );
+
+        $normalizers = \array_fill(0, $count, null);
+
+        $normalizers = \array_map(function (int $index) use ($json, $normalize) {
+            $normalized = $normalize(
+                $json,
+                $index
+            );
+
+            if (0 < $index) {
+                $json = $normalize(
+                    $json,
+                    $index - 1
+                );
+            }
+
+            $normalizer = $this->prophesize(NormalizerInterface::class);
+
+            $normalizer
+                ->normalize(Argument::exact($json))
+                ->shouldBeCalled()
+                ->willReturn($normalized);
+
+            return $normalizer->reveal();
+        }, \array_keys($normalizers));
+
+        $normalizer = new ChainNormalizer(...$normalizers);
+
+        $this->assertSame($normalized, $normalizer->normalize($json));
+    }
+}