diff --git a/src/Json/JsonFile.php b/src/Json/JsonFile.php
index c543845..1f02555 100644
--- a/src/Json/JsonFile.php
+++ b/src/Json/JsonFile.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Foxy package.
  *
@@ -11,43 +13,32 @@
 
 namespace Foxy\Json;
 
-use Composer\Json\JsonFile as BaseJsonFile;
-
 /**
  * The JSON file.
  *
  * @author François Pluchino <francois.pluchino@gmail.com>
  */
-class JsonFile extends BaseJsonFile
+final class JsonFile extends \Composer\Json\JsonFile
 {
     /**
-     * @var string[]
-     */
-    private $arrayKeys;
-
-    /**
-     * @var int
-     */
-    private $indent;
-
-    /**
-     * @var string[]
+     * @psalm-var string[]|null
      */
-    private static $encodeArrayKeys = array();
-
+    private array $arrayKeys = [];
+    private int|null $indent = null;
     /**
-     * @var int
+     * @psalm-var string[]
      */
-    private static $encodeIndent = JsonFormatter::DEFAULT_INDENT;
+    private static array $encodeArrayKeys = [];
+    private static int $encodeIndent = JsonFormatter::DEFAULT_INDENT;
 
     /**
      * Get the list of keys to be retained with an array representation if they are empty.
      *
-     * @return string[]
+     * @psalm-return string[]
      */
-    public function getArrayKeys()
+    public function getArrayKeys(): array
     {
-        if (null === $this->arrayKeys) {
+        if ([] === $this->arrayKeys) {
             $this->parseOriginalContent();
         }
 
@@ -56,10 +47,8 @@ public function getArrayKeys()
 
     /**
      * Get the indent for this json file.
-     *
-     * @return int
      */
-    public function getIndent()
+    public function getIndent(): int
     {
         if (null === $this->indent) {
             $this->parseOriginalContent();
@@ -68,10 +57,7 @@ public function getIndent()
         return $this->indent;
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function read()
+    public function read(): array
     {
         $data = parent::read();
         $this->getArrayKeys();
@@ -80,22 +66,19 @@ public function read()
         return $data;
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function write(array $hash, int $options = 448)
+    public function write(array $hash, int $options = 448): void
     {
         self::$encodeArrayKeys = $this->getArrayKeys();
         self::$encodeIndent = $this->getIndent();
         parent::write($hash, $options);
-        self::$encodeArrayKeys = array();
-        self::$encodeIndent = JsonFormatter::DEFAULT_INDENT;
+        self::$encodeArrayKeys = [];
+        self::$encodeIndent = 4;
     }
 
     /**
      * {@inheritdoc}
      */
-    public static function encode($data, int $options = 448, string $indent = self::INDENT_DEFAULT): string
+    public static function encode(mixed $data, int $options = 448, string $indent = self::INDENT_DEFAULT): string
     {
         $result = parent::encode($data, $options, $indent);
 
@@ -105,7 +88,7 @@ public static function encode($data, int $options = 448, string $indent = self::
     /**
      * Parse the original content.
      */
-    private function parseOriginalContent()
+    private function parseOriginalContent(): void
     {
         $content = $this->exists() ? file_get_contents($this->getPath()) : '';
         $this->arrayKeys = JsonFormatter::getArrayKeys($content);
diff --git a/src/Json/JsonFormatter.php b/src/Json/JsonFormatter.php
index 3b031bf..4927424 100644
--- a/src/Json/JsonFormatter.php
+++ b/src/Json/JsonFormatter.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of the Foxy package.
  *
@@ -11,44 +13,40 @@
 
 namespace Foxy\Json;
 
-use Composer\Json\JsonFormatter as ComposerJsonFormatter;
-
 /**
  * Formats JSON strings with a custom indent.
  *
  * @author François Pluchino <francois.pluchino@gmail.com>
  */
-class JsonFormatter
+final class JsonFormatter
 {
-    const DEFAULT_INDENT = 4;
-    const ARRAY_KEYS_REGEX = '/["\']([\w\d_\-.]+)["\']:\s\[]/';
-    const INDENT_REGEX = '/^[{\[][\r\n]([ ]+)["\']/';
+    public const DEFAULT_INDENT = 4;
+    public const ARRAY_KEYS_REGEX = '/["\']([\w\d_\-.]+)["\']:\s\[]/';
+    public const INDENT_REGEX = '/^[{\[][\r\n]([ ]+)["\']/';
 
     /**
      * Get the list of keys to be retained with an array representation if they are empty.
      *
-     * @param string $content The content
+     * @param string $content The content.
      *
-     * @return string[]
+     * @psalm-return string[] The list of keys to be retained with an array representation if they are empty.
      */
-    public static function getArrayKeys($content)
+    public static function getArrayKeys(string $content): array
     {
         preg_match_all(self::ARRAY_KEYS_REGEX, trim($content), $matches);
 
-        return !empty($matches) ? $matches[1] : array();
+        return !empty($matches) ? $matches[1] : [];
     }
 
     /**
      * Get the indent of file.
      *
      * @param string $content The content
-     *
-     * @return int
      */
-    public static function getIndent($content)
+    public static function getIndent(string $content): int
     {
         $indent = self::DEFAULT_INDENT;
-        preg_match(self::INDENT_REGEX, trim($content), $matches);
+        \preg_match(self::INDENT_REGEX, \trim($content), $matches);
 
         if (!empty($matches)) {
             $indent = \strlen($matches[1]);
@@ -60,42 +58,79 @@ public static function getIndent($content)
     /**
      * Format the data in JSON.
      *
-     * @param string   $json       The original JSON
-     * @param string[] $arrayKeys  The list of keys to be retained with an array representation if they are empty
-     * @param int      $indent     The space count for indent
-     * @param bool     $formatJson Check if the json must be formatted
+     * @param string $json The original JSON.
+     * @param array $arrayKeys The list of keys to be retained with an array representation if they are empty.
+     * @param int $indent The space count for indent.
+     * @param bool $formatJson Check if the json must be formatted.
      *
      * @return string
      */
-    public static function format($json, array $arrayKeys = array(), $indent = self::DEFAULT_INDENT, $formatJson = true)
-    {
+    public static function format(
+        string $json,
+        array $arrayKeys = [],
+        $indent = self::DEFAULT_INDENT,
+        $formatJson = true
+    ): string {
         if ($formatJson) {
-            $json = ComposerJsonFormatter::format($json, true, true);
+            $json = self::formatInternal($json, true, true);
         }
-
+    
         if (4 !== $indent) {
-            $json = str_replace('    ', sprintf('%'.$indent.'s', ''), $json);
+            $json = \str_replace('    ', \str_repeat(' ', $indent), $json);
         }
-
+    
         return self::replaceArrayByMap($json, $arrayKeys);
     }
 
+    /**
+     * Format the data in JSON.
+     *
+     * @param bool $unescapeUnicode Un escape unicode.
+     * @param bool $unescapeSlashes Un escape slashes.
+     */
+    private static function formatInternal(string $json, bool $unescapeUnicode, bool $unescapeSlashes): string
+    {
+        $array = \json_decode($json, true);
+    
+        if ($unescapeUnicode) {
+            \array_walk_recursive($array, function (&$item) {
+                if (\is_string($item)) {
+                    $item = \preg_replace_callback('/\\\\u([0-9a-fA-F]{4})/', function ($match) {
+                        return \mb_convert_encoding(\pack('H*', $match[1]), 'UTF-8', 'UCS-2BE');
+                    }, $item);
+                }
+            });
+        }
+    
+        if ($unescapeSlashes) {
+            \array_walk_recursive($array, function (&$item) {
+                if (\is_string($item)) {
+                    $item = \str_replace('\\/', '/', $item);
+                }
+            });
+        }
+    
+        return \json_encode($array, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
+    }
+
     /**
      * Replace the empty array by empty map.
      *
-     * @param string   $json      The original JSON
-     * @param string[] $arrayKeys The list of keys to be retained with an array representation if they are empty
+     * @param string $json The original JSON.
+     * @param array $arrayKeys The list of keys to be retained with an array representation if they are empty.
+     * 
+     * @psalm-param string[] $arrayKeys The list of keys to be retained with an array representation if they are empty.
      *
      * @return string
      */
-    private static function replaceArrayByMap($json, array $arrayKeys)
+    private static function replaceArrayByMap(string $json, array $arrayKeys): string
     {
-        preg_match_all(self::ARRAY_KEYS_REGEX, $json, $matches, PREG_SET_ORDER);
+        \preg_match_all(self::ARRAY_KEYS_REGEX, $json, $matches, PREG_SET_ORDER);
 
         foreach ($matches as $match) {
             if (!\in_array($match[1], $arrayKeys, true)) {
-                $replace = str_replace('[]', '{}', $match[0]);
-                $json = str_replace($match[0], $replace, $json);
+                $replace = \str_replace('[]', '{}', $match[0]);
+                $json = \str_replace($match[0], $replace, $json);
             }
         }
 
diff --git a/resources/doc/config.md b/src/Resources/doc/config.md
similarity index 100%
rename from resources/doc/config.md
rename to src/Resources/doc/config.md
diff --git a/resources/doc/events.md b/src/Resources/doc/events.md
similarity index 100%
rename from resources/doc/events.md
rename to src/Resources/doc/events.md
diff --git a/resources/doc/faqs.md b/src/Resources/doc/faqs.md
similarity index 100%
rename from resources/doc/faqs.md
rename to src/Resources/doc/faqs.md
diff --git a/resources/doc/index.md b/src/Resources/doc/index.md
similarity index 100%
rename from resources/doc/index.md
rename to src/Resources/doc/index.md
diff --git a/resources/doc/usage.md b/src/Resources/doc/usage.md
similarity index 100%
rename from resources/doc/usage.md
rename to src/Resources/doc/usage.md
diff --git a/tests/Json/JsonFormatterTest.php b/tests/Json/JsonFormatterTest.php
index c93b95d..b499d11 100644
--- a/tests/Json/JsonFormatterTest.php
+++ b/tests/Json/JsonFormatterTest.php
@@ -51,8 +51,8 @@ public function testGetIndent()
     }
 
     public function testFormat()
-    {
-        $expected = <<<'JSON'
+{
+    $expected = <<<'JSON'
 {
   "name": "test",
   "contributors": [],
@@ -62,16 +62,16 @@ public function testFormat()
   "devDependencies": {}
 }
 JSON;
-        $data = array(
-            'name' => 'test',
-            'contributors' => array(),
-            'dependencies' => array(
-                '@foo/bar' => '^1.0.0',
-            ),
-            'devDependencies' => array(),
-        );
-        $content = json_encode($data);
+    $data = array(
+        'name' => 'test',
+        'contributors' => array(),
+        'dependencies' => array(
+            '@foo/bar' => '^1.0.0',
+        ),
+        'devDependencies' => array(),
+    );
+    $content = json_encode($data);
 
-        static::assertSame($expected, JsonFormatter::format($content, array('contributors'), 2));
-    }
+    static::assertSame($expected, JsonFormatter::format($content, array('contributors'), 2));
+}
 }