tryFn.ts

class Error {
  public readonly generatedAt: Date;

  constructor(public readonly message: string) {
    this.generatedAt = new Date();
  }
}

const isError = (input: unknown): input is Error => input instanceof Error;

function tryFn<F extends (...args: any[]) => any>(
  fn: F,
  ...input: Parameters<F>
): ReturnType<F> | Error {
  let result: ReturnType<F> | Error;
  try {
    result = fn(input);
  } catch (e) {
    result = new Error(e.toString());
  }
  return result;
}

const something = async () => {
  const log = (i: string) => `I logged: ${i}`;
  const resultSync = tryFn(log, 'hi');
  if (isError(resultSync)) {
    console.error(`[Sync ERROR at ${resultSync.generatedAt}] ${resultSync.message}`);
  } else {
    console.info(resultSync); // type is correct
  }

  const sleep = async () => setTimeout(null, 1000);
  const resultAsync = await tryFn(sleep);
  if (isError(resultAsync)) {
    console.error(`[Async ERROR at ${resultAsync.generatedAt}] ${resultAsync.message}`);
  } else {
    console.info(resultAsync); // type is correct
  }
};