util.types
A collection of type-check predicates for built-in JavaScript and Node values.
Syntax
util.types.isX(value)Parameters
| Name | Type | Required | Description |
|---|---|---|---|
value | any | Yes | The value passed to a specific predicate such as `isPromise`, `isDate`, or `isTypedArray`. |
Returns
boolean — true if the value matches the checked type.
Examples
import { types } from 'node:util';
console.log(types.isPromise(Promise.resolve()));
console.log(types.isDate(new Date()));
Output
true
true
import { types } from 'node:util';
console.log(types.isAsyncFunction(async () => {}));
console.log(types.isNativeError(new TypeError()));
Output
true
true
Notes
More reliable than `instanceof` across realms/contexts (e.g. values
from `vm` or worker threads). Useful when introspecting unknown
values in libraries.