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ReferenceError

The ReferenceError object represents an error when a non-existent variable is referenced.

Syntax

new ReferenceError([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 ReferenceError is thrown when trying to dereference a variable that has not been declared.

Properties

ReferenceError.prototype
Allows the addition of properties to an ReferenceError object.

ReferenceError instances

Properties

ReferenceError.prototype.constructor
Specifies the function that created an instance's prototype.
ReferenceError.prototype.message
Error message. Although ECMA-262 specifies that ReferenceError should provide its own message property, in SpiderMonkey, it inherits Error.prototype.message.
ReferenceError.prototype.name
Error name. Inherited from Error.
ReferenceError.prototype.fileName
Path to file that raised this error. Inherited from Error.
ReferenceError.prototype.lineNumber
Line number in file that raised this error. Inherited from Error.
ReferenceError.prototype.columnNumber
Column number in line that raised this error. Inherited from Error.
ReferenceError.prototype.stack
Stack trace. Inherited from Error.

Methods

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

Examples

Catching a ReferenceError

try {
  var 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.fileName);                  // "Scratchpad/1"
  console.log(e.lineNumber);                // 2
  console.log(e.columnNumber);              // 6
  console.log(e.stack);                     // "@Scratchpad/2:2:7\n"
}

Creating a ReferenceError

try {
  throw new ReferenceError('Hello', 'someFile.js', 10);
} catch (e) {
  console.log(e instanceof ReferenceError); // true
  console.log(e.message);                   // "Hello"
  console.log(e.name);                      // "ReferenceError"
  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

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support Yes Yes 1 Yes Yes Yes
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support Yes Yes Yes 4 Yes Yes Yes
Server
Node.js
Basic support Yes

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ReferenceError