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".

js
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

js
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
}