TypeError

The TypeError object represents an error when a value is not of the expected type.

Syntax

new TypeError([message[, fileName[, lineNumber]]])

Parameters

message

Optional. Human-readable description of the error

fileName

Optional. The name of the file containing the code that caused the exception

lineNumber

Optional. The line number of the code that caused the exception

Description

A TypeError is thrown when an operand or argument passed to a function is incompatible with the type expected by that operator or function.

Properties

TypeError.prototype

Allows the addition of properties to a TypeError object.

Methods

The global TypeError contains no methods of its own, however, it does inherit some methods through the prototype chain.

TypeError instances

Properties

TypeError.prototype.constructor

Specifies the function that created an instance's prototype.

TypeError.prototype.message

Error message. Although ECMA-262 specifies that TypeError should provide its own message property, in SpiderMonkey, it inherits Error.prototype.message.

TypeError.prototype.name

Error name. Inherited from Error.

TypeError.prototype.fileName

Path to file that raised this error. Inherited from Error.

TypeError.prototype.lineNumber

Line number in file that raised this error. Inherited from Error.

TypeError.prototype.columnNumber

Column number in line that raised this error. Inherited from Error.

TypeError.prototype.stack

Stack trace. Inherited from Error.

Methods

Although the TypeError prototype object does not contain any methods of its own, TypeError instances do inherit some methods through the prototype chain.

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

Browser compatibilityUpdate compatibility data on GitHub

See also

• Error
• TypeError.prototype