async/await utility function for more elegant handling of failures rather than adding try/catch blocks everywhere. This allows us to also know what exactly failed.

async-await-handler.ts

interface IAsyncAwait<T, R> {
  error: R|Error|null;
  response: T|null;
}

// async/await utility function for more elegant handling of failures
const asyncAwaitHandler: <A, B>(promise: Promise<A>) => Promise<IAsyncAwait<A|null, B|null>> = <A, B>(promise: Promise<A>): Promise<IAsyncAwait<A|null, B|null>> => {
  return promise
    .then((response: A): IAsyncAwait<A, null> => ({ error: null, response }))
    .catch((error: B): Promise<IAsyncAwait<null, B>> => Promise.resolve({ error, response: null }));
};

// example promise
const myPromise = (errorMe?: any): Promise<string> => {
  if (errorMe) {
    return Promise.reject('error occurred');
  }

  return Promise.resolve('success');
};

// usage of the utility function
const usage = async (shouldIThrow?: any): Promise<void> => {
  const data: IAsyncAwait<string|null, any> = await asyncAwaitHandler(myPromise(shouldIThrow));

  if (data.error) {
    console.log(data.error);
  } else {
    console.log(data.response);
  }


  // or we can use destructuring
  /**
   const { error, response }: IAsyncAwait<string|null, any> = await asyncAwaitHandler(myPromise(shouldIThrow));

   if (error) {
    console.log(error);
  } else {
    console.log(response);
  }
   **/
};

usage(); // prints 'success'
usage('throw me'); // prints 'error occurred'