An express middleware for hydrating dates

date-middleware.ts

const dateFormat = /^-?\d+-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/;

function hydrator(key: string, value: any) {
  if (typeof value === 'string' && dateFormat.test(value)) {
    return new Date(value);
  }

  return value;
}

export function hydrateDates(req: Request, res: Response, next: any) {
  // if we don't pass any data, then this doesn't apply
  if (extractRequestData(req) === undefined) {
    next();
  } else {
    const dataAsString = JSON.stringify(extractRequestData(req));
    const hydratedData = JSON.parse(dataAsString, hydrator);

    req.body.data = hydratedData;
    next();
  }
}