@nick/is/set

isSet

Signature

function isSet<T>(it: unknown): it is Set<T>;

Checks if a given value is a Set instance. This is a more reliable check than it instanceof Set because it also works across different realms.

It's also more strict than instanceof operations, only recognizing an object as a Set instance if it was created with a valid construct operation of either the Set constructor or a subclass of it. As such, Object.create(Set.prototype) and similar avenues will return false.

Parameters

Name	Info
it	The value to check.

Returns

true if the value is a Set instance, false otherwise.

Category

Keyed Collections

Examples

import { isSet } from "jsr:@nick/is/set";

isSet(new Set()); // true
isSet(new WeakSet()); // false
isSet(new Map()); // false
isSet([]); // false
isSet(Object.create(Set.prototype)); // false