Add reverseParse function

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## PENDING
+
+- Add `Parser::reverseParse()` doing the opposite of `Parser::parse()` [#10](https://github.com/mapado/request-fields-parser/pull/10) by [@nickinthebox](https://github.com/nickinthebox)
+
 ## 3.0.3
 
 - Test array access + avoid warning [#9](https://github.com/mapado/request-fields-parser/pull/9) by [@jdeniau](https://github.com/jdeniau)

README.md

@@ -19,6 +19,8 @@ Convert string like `id,firstname,lastname,jobs{startDate,position,company{id,re
 
 You can think of it like an [explode](https://php.net/explode) on steroids.
 
+Also implement a `reverseParse` function for the opposite transformation.
+
 ## Installation
 
 ```sh
@@ -34,6 +36,8 @@ use Mapado\RequestFieldsParser\Parser;
 $parser = new Parser();
 
 $outArray = $parser->parse($string);
+
+$outString = $parser->reverseParse($array);
 ```
 
 ## Extensibility
@@ -55,7 +59,7 @@ class ExtendedParser implements ParserInterface
         $this->decoratedParser = $decoratedParser;
     }
 
-    public function parse(string $sttring): array
+    public function parse(string $string): array
     {
         // do stuff and return an array
     }

src/Parser.php

@@ -27,6 +27,28 @@ public function parse(string $string): Fields
         return $out;
     }
 
+    /**
+     * @param iterable<int|string, mixed>|string $fields
+     */
+    public function reverseParse($fields): string
+    {
+        if (is_string($fields)) {
+            return $fields;
+        }
+
+        $fieldsStr = '';
+        foreach ($fields as $fieldName => $fieldValue) {
+            if (is_array($fieldValue) || $fieldValue instanceof \Traversable) {
+                $fieldsStr .= $fieldName . '{' . $this->reverseParse($fieldValue) . '},';
+            } else {
+                $fieldsStr .= (true === $fieldValue ? $fieldName : $fieldValue) . ',';
+            }
+        }
+        $fieldsStr = rtrim($fieldsStr, ',');
+
+        return $fieldsStr;
+    }
+
     private function treatCurrent(bool $isFirst): Fields
     {
         if ($isFirst) {

tests/ParserTest.php

@@ -22,6 +22,7 @@ public function testEmpty(): void
         $this->assertSame([], $parsed->toArray());
     }
 
+
     public function testOneLevelParser(): void
     {
         $testedInstance = new Parser();
@@ -83,4 +84,75 @@ public function testMultiLevelParser(): void
             iterator_to_array($parsed)['eventDate'],
         );
     }
+
+
+    public function testReverseEmpty(): void
+    {
+        $testedInstance = new Parser();
+
+        $reverseParsed = $testedInstance->reverseParse([]);
+
+        $this->assertIsString($reverseParsed);
+        $this->assertSame('', $reverseParsed);
+    }
+
+    public function testOneLevelReverseParser(): void
+    {
+        $testedInstance = new Parser();
+        $reverseParsed = $testedInstance->reverseParse(['@id', 'title', 'eventDate']);
+        $this->assertIsString($reverseParsed);
+        $this->assertSame('@id,title,eventDate', $reverseParsed);
+    }
+
+    public function testMultiLevelReverseParser(): void
+    {
+        $source = [
+            '@id',
+            'title',
+            'eventDate' => [
+                '@id',
+                'startDate',
+                'ticketing' => [
+                    '@id',
+                ],
+            ],
+        ];
+
+        $testedInstance = new Parser();
+        $reverseParsed = $testedInstance->reverseParse($source);
+        $this->assertIsString($reverseParsed);
+        $this->assertSame('@id,title,eventDate{@id,startDate,ticketing{@id}}', $reverseParsed);
+
+        $sourceWithBooleans = [
+            '@id' => true,
+            'title' => true,
+            'eventDate' => [
+                '@id' => true,
+                'startDate' => true,
+                'ticketing' => [
+                    '@id' => true,
+                ],
+            ],
+        ];
+
+        $reverseParsedWithBooleans = $testedInstance->reverseParse($sourceWithBooleans);
+        $this->assertIsString($reverseParsedWithBooleans);
+        $this->assertSame('@id,title,eventDate{@id,startDate,ticketing{@id}}', $reverseParsedWithBooleans);
+    }
+
+
+    public function testReversability(): void
+    {
+        $testedInstance = new Parser();
+
+        $sample = '@id,title,eventDate';
+        $parsedSample = $testedInstance->parse($sample);
+        $reverseParsedSample = $testedInstance->reverseParse($parsedSample);
+        $this->assertSame($sample, $reverseParsedSample);
+
+        $sample = '@id,title,eventDate{@id,startDate,ticketing{@id}}';
+        $parsedSample = $testedInstance->parse($sample);
+        $reverseParsedSample = $testedInstance->reverseParse($parsedSample);
+        $this->assertSame($sample, $reverseParsedSample);
+    }
 }