async and callback function

const f = async (param, callback=false) => {
  try {
    const data = await request.get(url);
    if(callback) callback(null, data); // If callback, then call it
    return data; // Then return data, it returns as a promise.resolve automatically
  } catch(err) {
    if(callback) callback(err); // If callback, then call it
    throw err; // Then throw, it returns promise.reject automatically
  }
}

f(1).then(console.log); // call as promise
f(1, console.log); // call as callback