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.

TheReferenceError 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 aserializable object, so it can be cloned withstructuredClone() or copied betweenWorkers usingpostMessage().

ReferenceError is a subclass ofError.

Constructor

ReferenceError(): Creates a newReferenceError object.

Instance properties

Also inherits instance properties from its parentError.

These properties are defined onReferenceError.prototype and shared by allReferenceError instances.

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

Instance methods

Inherits instance methods from its parentError.

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}