source/InputOutputFiles.php
public function getArrayFromJsonFile($strFilePath, $strFileName)
    {
        $jSonContent   = $this->getFileJsonContent($strFilePath, $strFileName);
        $arrayToReturn = json_decode($jSonContent, true);
        if (json_last_error() != JSON_ERROR_NONE) {
            $fName = $this->gluePathWithFileName($strFilePath, $strFileName);
            throw new \RuntimeException(sprintf('Unable to interpret JSON from %s file...', $fName));
        }
        return $arrayToReturn;
    }
public function getArrayFromJsonFile($strFilePath, $strFileName)
    {
        $jSonContent   = $this->getFileJsonContent($strFilePath, $strFileName);
        $arrayToReturn = json_decode($jSonContent, true);
        if (json_last_error() != JSON_ERROR_NONE) {
            $fName = $this->gluePathWithFileName($strFilePath, $strFileName);
            throw new \RuntimeException(sprintf('Unable to interpret JSON from %s file...', $fName));
        }
        return $arrayToReturn;
    }
returns an array with non-standard holidays from a JSON file

@param string $strFileName
@return mixed