@nick/is/promise

isPromise

Signature

function isPromise<T>(it: unknown): it is Promise<T>;

Checks if a given value is a native Promise instance. This is a more reliable alternative to it instanceof Promise because it also works across different realms (e.g., iframes, workers, etc.).

Note: This guard does not consider custom promise-like objects with .then methods to be promises. If your use case requires that, use isPromiseLike.

Parameters

Name	Info
it	The value to check.

Returns

true if the value is a Promise, false otherwise.

Category

Async/Await

Examples

import { isPromise } from "jsr:@nick/is/promise";

console.log(isPromise(Promise.resolve())); // true
console.log(isPromise({ then: () => {} })); // false
console.log(isPromise({})); // false