result-kit v0.0.2

Result Kit

A minimal typescript implementation of a result type. Inspired by Rust's Result.

Installation:

To install result-kit run:

bun install result-kit

Or

yarn add result-kit

Or

npm install result-kit

Before:

async function fetchDogs(): Promise<unknown> {
  const dogs = await fetch("/dog");
  return dogs;
}
function parseJson(result: unknown): unknown {
  return JSON.parse(result);
}

await function runExample() {
  const dogs = await fetchDogs();
  parseJson(dogs);
};

The major problem with the implementation above is that the function signature doesn't indicate to the caller that it might throw an error so the developer might not get to handle the scenario where there is an error and would only find out when they run the piece of code.

With Results:

import { runSync, runAsync } from "result-kit";

async function fetchDogs(): Promise<Result<unknown, Error>> {
  return runAsync(async () => {
    const dogs = await fetch("/dog");
    return dogs;
  });
}
function parseJson(result): Result<unknown, Error> {
  return runSync(() => JSON.parse(result));
}

await function runExample() {
  const dogsResult = await fetchDogs();

  if (!dogsResult.ok) {
    // Handle error
    return;
  }

  parseJson(dogsResult.value);
};

With Results the function signature tells the caller that it returns a result which the caller has to check if the ok field is true (success) to be able to use (unwrap) the value field, otherwise ok is false (failure) and we can also access the error field with the appropriate error.

runSync and runAsync are just wrapper functions that uses the the underlying err and ok functions to handle both synchronous and asynchronous operations respectfully.