toResult

Converts a PromiseLike to a Promise<Result>

Usage

Converts a PromiseLike to a Promise<Result>.

import { toResult, Result } from 'radashi'

const good = async (): Promise<number> => 1
const bad = async (): Promise<number> => {
  throw new Error('bad')
}

const goodResult = await toResult(good())
// => [undefined, 1]

const badResult = await toResult(bad())
// => [Error('bad'), undefined]

Throwing non-Error values

If the given promise throws a non-Error value, it will be rethrown. This ensures the Result always contains an Error value or undefined.

// This won't catch the rejected promise, because it was
// rejected with a string, not an Error.
const res = await toResult(Promise.reject('test error'))

Synchronous errors

This function won’t catch synchronous errors. Only rejected promises are converted to an Err.

function bad() {
  if (Math.random() > 0.5) {
    // ⚠️ This error won't be caught by `toResult`. To fix this, add
    // the `async` keyword to the containing function.
    throw new Error('bad')
  }
  return new Promise((resolve, reject) => {
    /* ... */
  })
}

const res = await toResult(bad())
//    ^? Promise<Result<number>>