const jayZDetails = { age: 48, demeanorAge: 78 };

const intermediateResult = mapObj(stringifyNumber, jayZDetails);
// => { age: 'forty eight', demeanorAge: 'seventy eight' }

const finalResult = mapObj(addAgeSuffix, intermediateResult));
// => { age: 'forty eight years old', demeanorAge: 'seventy eight years old' }

result['demeanorAge'] //=> 'seventy eight years old';