How to use JSON.parse reviver parameter to parse date string

Question

My JSON string contains a date field that returns such a value:

\"2009-04-04T22:55:16.0000000-04:00\"

I am particularly interested in parsi

Answer 1

Drop-in solution

const jsonDateRegexp = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})\.(\d{3})Z$/;

function jsonRetriever(key: string, value: any) {
  // let's try to detect input we dont have to parse early, so this function is as fast as possible
  if (typeof value !== 'string') {
    return value;
  }

  const dateMatch = jsonDateRegexp.exec(value);

  if (!dateMatch) {
    return value;
  }

  return new Date(
    Date.UTC(
      +dateMatch[1],
      +dateMatch[2] - 1,
      +dateMatch[3],
      +dateMatch[4],
      +dateMatch[5],
      +dateMatch[6],
      +dateMatch[7],
    ),
  );
}

export function parseJsonWithDates(input: string) {
  return JSON.parse(input, jsonRetriever);
}