TypeError

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

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

TypeError is a subclass of Error.

Constructor

TypeError()

Creates a new TypeError object.

Instance properties

Also inherits instance properties from its parent Error.

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

TypeError.prototype.constructor

The constructor function that created the instance object. For TypeError instances, the initial value is the TypeError constructor.

TypeError.prototype.name

Represents the name for the type of error. For TypeError.prototype.name, the initial value is "TypeError".

Instance methods

Inherits instance methods from its parent Error.

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.fileName); // "Scratchpad/1"
  console.log(e.lineNumber); // 2
  console.log(e.columnNumber); // 2
  console.log(e.stack); // "@Scratchpad/2:2:3\n"
}

Creating a TypeError

try {
  throw new TypeError("Hello", "someFile.js", 10);
} catch (e) {
  console.log(e instanceof TypeError); // true
  console.log(e.message); // "Hello"
  console.log(e.name); // "TypeError"
  console.log(e.fileName); // "someFile.js"
  console.log(e.lineNumber); // 10
  console.log(e.columnNumber); // 0
  console.log(e.stack); // "@Scratchpad/2:2:9\n"
}

Specifications

Specification
ECMAScript Language Specification
# sec-native-error-types-used-in-this-standard-typeerror

Browser compatibility

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See also