icodealone

static public function asString(array $a) : string
    {
        return array_reduce(array_keys($a), function($str, $sectionName) use ($a) {
            $sub = $a[$sectionName];
            return $str . "[$sectionName]" . PHP_EOL .
                array_reduce(array_keys($sub), function($str, $key) use($sub) {
                    return $str . $key . '=' . $sub[$key] . PHP_EOL;
                }) . PHP_EOL;
        });
    }

icodealone

function keyed_array_map($fn, array $a) : array
{
    return array_column(array_map($fn, array_keys($a), $a), 1, 0);
}

icodealone

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Outputs the date/time

Resources:
  TimeFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs8.10