function types.isWeakSet
          
Usage in Deno
import { types } from "node:util"; const { isWeakSet } = types;
isWeakSet(object: unknown): object is WeakSet<object> 
      Returns true if the value is a built-in WeakSet instance.
util.types.isWeakSet(new WeakSet()); // Returns true
object is WeakSet<object>