A better way to handle errors

• File structure remains flat, unlike with nested try...catch
• Both data and errors are declared with const, unlike with non-nested try...catch
• Both data and errors are non-nullable, once an early return occurs if the other is null
• Both data and errors are available at the top level, unlike with try...catch or promises
• Work with errors that are always Error objects by default, without compromising type-safety, unlike with try...catch or promises
• TypeScript support with optional generic parameters for data and error types

$ npm install betterr

import { betterr, betterrSync } from 'betterr';
// const { betterr, betterrSync } = require('betterr');

const { data: user, err } = await betterr(() => getRandomUser());
//            ^?    ^? user: User | null, err: Error | null

if (err) {
  // ^? err: Error
  return;
}

return user;
//     ^? user: User

• betterr can be used with both asynchronous and synchronous callbacks
• betterrSync can only be used with synchronous callbacks, but avoids wrapping the data in a promise, so await is not necessary

Both betterr and betterrSync are generic, so the type of data and error can be provided. The callback return type must be assignable to the first generic parameter (for data).

/**
 * const betterrSync: <TData, TError = Error>(callback: () => TData) =>
 * | { data: TData; err: null }
 * | { data: null; err: TError }
 */

const { data, err } = betterrSync<User, MyError>(() => ({
  //    ^?    ^? data: User | null, err: MyError | null
  userId: 1,
}));