ReferenceError

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

* Some parts of this feature may have varying levels of support.

The ReferenceError object represents an error when a variable that doesn't exist (or hasn't yet been initialized) in the current scope is referenced.

ReferenceError is a serializable object, so it can be cloned with structuredClone() or copied between Workers using postMessage().

ReferenceError is a subclass of Error.

Constructor

ReferenceError(): Creates a new ReferenceError object.

Instance properties

Also inherits instance properties from its parent Error.

These properties are defined on ReferenceError.prototype and shared by all ReferenceError instances.

ReferenceError.prototype.constructor: The constructor function that created the instance object. For ReferenceError instances, the initial value is the ReferenceError constructor.
ReferenceError.prototype.name: Represents the name for the type of error. For ReferenceError.prototype.name, the initial value is "ReferenceError".

Instance methods

Inherits instance methods from its parent Error.

Examples

Catching a ReferenceError

try { let a = undefinedVariable; } catch (e) { console.log(e instanceof ReferenceError); // true console.log(e.message); // "undefinedVariable is not defined" console.log(e.name); // "ReferenceError" console.log(e.stack); // Stack of the error }

Creating a ReferenceError

try { throw new ReferenceError("Hello"); } catch (e) { console.log(e instanceof ReferenceError); // true console.log(e.message); // "Hello" console.log(e.name); // "ReferenceError" console.log(e.stack); // Stack of the error }

Specifications

Specification
ECMAScript® 2026 Language Specification # sec-native-error-types-used-in-this-standard-referenceerror