Add ToKebabCase Filter

Author: charjr

docs/filters.md

@@ -443,6 +443,32 @@ The above example will output the following
 Result was valid
 ```
 
+### ToKebabCase
+
+```php
+new Membrane\Filter\String\ToKebabCase();
+```
+
+Converts string into KebabCase (i.e. no whitespaces, uppercase for first letter of each word).
+
+```php
+$string = "helloThere have_you heard-of OpenAPI?";
+$pascalCase = new Membrane\Filter\String\ToKebabCase();
+
+$result = $pascalCase->filter($string);
+
+echo $result->value;
+echo $result->isValid() ? 'is valid' : 'is invalid';
+```
+
+The above example will output the following
+
+```text
+hellothere-have-you-heard-of-openapi?
+```
+
+Note that _helloThere_ became _hellothere_. `ToKebabCase` does not split on capitals, otherwise _OpenAPI_ would become _open-a-p-i_ which is a less desirable result.
+
 ### ToPascalCase
 
 ```php

src/Filter/String/ToKebabCase.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Membrane\Filter\String;
+
+use Membrane\Filter;
+use Membrane\Result\Message;
+use Membrane\Result\MessageSet;
+use Membrane\Result\Result;
+
+class ToKebabCase implements Filter
+{
+    public function filter(mixed $value): Result
+    {
+        if (!is_string($value)) {
+            return Result::invalid($value, new MessageSet(null, new Message(
+                'Expected string value, received %s',
+                [gettype($value)],
+            )));
+        }
+
+        $result = preg_replace(['#[\s\-.,_/]+#', '#[^[:alnum:]-]#'], ['-'], $value);
+        assert(is_string($result));
+
+        $result = mb_strtolower($result);
+
+        return Result::noResult($result);
+    }
+
+    public function __toString(): string
+    {
+        return 'Convert text to kebab-case';
+    }
+
+    public function __toPHP(): string
+    {
+        return sprintf('new %s()', self::class);
+    }
+}

tests/Filter/String/ToKebabCaseTest.php

@@ -0,0 +1,113 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Filter\String;
+
+use Membrane\Filter\String\ToKebabCase;
+use Membrane\Result\{Message, MessageSet, Result};
+use PHPUnit\Framework\Attributes\{CoversClass, DataProvider, Test, TestDox, UsesClass};
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(ToKebabCase::class)]
+#[UsesClass(Message::class)]
+#[UsesClass(MessageSet::class)]
+#[UsesClass(Result::class)]
+class ToKebabCaseTest extends TestCase
+{
+    #[Test]
+    #[TestDox('toString() returns a description of its behaviour')]
+    public function itCaststoString(): void
+    {
+        self::assertSame(
+            'Convert text to kebab-case',
+            (new ToKebabCase())->__toString()
+        );
+    }
+
+    #[Test]
+    #[TestDox('__toPHP() returns a string of evaluable PHP')]
+    public function itCaststoPHP(): void
+    {
+        $sut = new ToKebabCase();
+
+        self::assertEquals($sut, eval('return ' . $sut->__toPHP() . ';'));
+    }
+
+    #[Test]
+    #[TestDox('It will return an invalid Result if it filters values that are not strings')]
+    public function returnsInvalidResultForNonStringValues(): void
+    {
+        $value = 5;
+        $expected = Result::invalid($value, new MessageSet(null, new Message(
+            'Expected string value, received %s',
+            [gettype($value)],
+        )));
+
+        self::assertEquals($expected, (new ToKebabCase())->filter($value));
+    }
+
+    #[Test]
+    #[TestDox('It filters strings to PascalCase')]
+    #[DataProvider('provideStringsToFilter')]
+    public function filtersStringsToKebabCase(string $value, Result $expected): void
+    {
+        self::assertEquals($expected, (new ToKebabCase())->filter($value));
+    }
+
+    public static function provideStringsToFilter(): array
+    {
+        return [
+            '"Hello, World!"' => [
+                '"Hello, World!"',
+                Result::noResult('hello-world'),
+            ],
+            'camelCase' => [
+                'camelCase',
+                Result::noResult('camelcase'),
+            ],
+            'kebab-case' => [
+                'kebab-case',
+                Result::noResult('kebab-case'),
+            ],
+            'kebabber------case' => [
+                'kebabber------case',
+                Result::noResult('kebabber-case'),
+            ],
+            'snake_case' => [
+                'snake_case',
+                Result::noResult('snake-case'),
+            ],
+            'snakiest_____case' => [
+                'snakiest_____case',
+                Result::noResult('snakiest-case'),
+            ],
+            'pets/{id}' => [
+                'pets/{id}',
+                Result::noResult('pets-id'),
+            ],
+            'http://petstore.swagger.io/{version}/pets/{id}' => [
+                'http://petstore.swagger.io/{version}/pets/{id}',
+                Result::noResult('http-petstore-swagger-io-version-pets-id'),
+            ],
+            'plain text' => [
+                'plain text',
+                Result::noResult('plain-text'),
+            ],
+            'plain 1text' => [
+                'plain 1text',
+                Result::noResult('plain-1text'),
+            ],
+            'plain 1 text' => [
+                'plain 1 text',
+                Result::noResult('plain-1-text'),
+            ],
+            'sTuPiD-_-cAsE' => [
+                'sTuPiD-_-cAsE',
+                Result::noResult('stupid-case'),
+            ],
+        ];
+    }
+
+
+}