ReferenceError

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

Syntax

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

Parameters

message Optional

Optional. Human-readable description of the error.

fileName Optional

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

lineNumber Optional

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

Examples

Catching a ReferenceError

try {
  let 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