ReferenceError - JavaScript | MDN (original) (raw)

Baseline

Widely available *

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

Browser compatibility

See also