rslt v0.0.3

RSLT

This is a very experimental and very opinionated implementation of a monadic Result type in TypeScript with enforced error handling, inspired by Rust's std::result and Austral's modeling of errors.

The goal of this library is to evaluate whether and how enforced error handling via monadic types affects the performance, maintainability and reliability of TypeScript and, to a lesser degree, JavaScript applications.

This library will forcefully crash your process and/or your UX whenever an unhandled exception or an unhandled rejection is detected.

All unhandled exceptions and rejections are considered as unrecoverable errors. Critically, rejecting promises returned by ifErrAsync() and ifOkAsync() callbacks are also considered as unrecoverable errors, effectively forcing developers to wrap all errors deemed as recoverable into Result instances via the err() function and making the handling of recoverable errors as type-safe as that of regular values.

This library should definitely not be used in production environments. Using it in other environments might also be unwise due to its experimental nature and lack of testing.

import { ok, err, empty, Result } from 'rslt';

const result = empty()
  .ifOk(() => ok<'hello'>('hello'))
  .ifErr(() => ok<'salut'>('salut'))
  .ifErrAsync(async () => err<'ciao'>('ciao'));

// The result constant is of type:
// Result<"hello", never> | Result<"salut", never> | Result<never, "ciao">

const value = await result.unwrapAsync();

// The value constant is of type:
// "hello" | "salut"