kotlin-node/node.util.types/isNativeErrorRaw

isNativeErrorRaw

external fun isNativeErrorRaw(value: Any?): Boolean(source)

Returns true if the value was returned by the constructor of a built-in Error type.

console.log(util.types.isNativeError(new Error()));  // true
console.log(util.types.isNativeError(new TypeError()));  // true
console.log(util.types.isNativeError(new RangeError()));  // true

Subclasses of the native error types are also native errors:

class MyError extends Error {}
console.log(util.types.isNativeError(new MyError()));  // true

A value being instanceof a native error class is not equivalent to isNativeError() returning true for that value. isNativeError() returns true for errors which come from a different realm while instanceof Error returns false for these errors:

import { createContext, runInContext } from 'node:vm';
import { types } from 'node:util';

const context = createContext({});
const myError = runInContext('new Error()', context);
console.log(types.isNativeError(myError)); // true
console.log(myError instanceof Error); // false

Conversely, isNativeError() returns false for all objects which were not returned by the constructor of a native error. That includes values which are instanceof native errors:

const myError = { __proto__: Error.prototype };
console.log(util.types.isNativeError(myError)); // false
console.log(myError instanceof Error); // true

Since

v10.0.0