useAsync

Gracefully handles a callback that returns a promise, wrapping the result in a discriminated tuple so you never need a try/catch.

import { useAsync } from "@oricardopestana/ts-utils";

AsyncResult

The return type is AsyncResult<ResolveData, RejectionReason> — a discriminated tuple:

type AsyncResult<ResolveData, RejectionReason> =
  | [data: ResolveData, reason: null]
  | [data: null, reason: RejectionReason];

When the promise resolves, the first element holds the data and the second is null.
When the promise rejects, the first element is null and the second holds the rejection reason.

Usage

const [data, error] = await useAsync(() => Promise.resolve(42));
// data  -> 42
// error -> null

const [data, error] = await useAsync(() => Promise.reject(new Error("Oops!")));
// data  -> null
// error -> Error("Oops!")

The callback can throw synchronously — errors are caught the same way:

const [data, error] = await useAsync(() => {
  throw new Error("Sync throw");
});
// data  -> null
// error -> Error("Sync throw")

The rejection reason type parameter defaults to Error, but non-Error values are also supported:

const [data, error] = await useAsync(() => Promise.reject("Oops!"));
// data  -> null
// error -> "Oops!"