Transformar imagen base64 a un archivo

fromBase64ToImg.php

<?php
 function fromBase64ToImg($imgBase64 , $dir , $name_file ){

        $pattern = '/data:image\/(.+);base64,(.*)/';
        preg_match($pattern, $imgBase64, $matches);

        $imageExtension = $matches[1];

        $encodedImageData = $matches[2];

        $decodedImageData = base64_decode($encodedImageData);
        $name = "{$name_file}.{$imageExtension}";

        file_put_contents("{$dir}/{$name}", $decodedImageData);
        return  "{$name}.{$imageExtension}";
  }

?>