TypeError

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.

TheTypeError object represents an error when an operation could not be performed, typically (but not exclusively) when a value is not of the expected type.

ATypeError may be thrown when:

an operand or argument passed to a function is incompatible with the type expected by that operator or function; or
when attempting to modify a value that cannot be changed; or
when attempting to use a value in an inappropriate way.

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

TypeError is a subclass ofError.

Constructor

TypeError(): Creates a newTypeError object.

Instance properties

Also inherits instance properties from its parentError.

These properties are defined onTypeError.prototype and shared by allTypeError instances.

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

Instance methods

Inherits instance methods from its parentError.

Examples

Catching a TypeError

try {  null.f();} catch (e) {  console.log(e instanceof TypeError); // true  console.log(e.message); // "null has no properties"  console.log(e.name); // "TypeError"  console.log(e.stack); // Stack of the error}

Creating a TypeError

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