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.

Methods

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

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 compatibility

See also

• Error
• ReferenceError.prototype