ReferenceError
The ReferenceError
object represents an error when a non-existent variable is referenced.
Syntax
JavaScript
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new ReferenceError([<var>message</var>[, <var>fileName</var>[, <var>lineNumber</var>]]])
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 ownmessage
property, in SpiderMonkey, it inheritsError.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
JavaScript
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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
JavaScript
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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
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. |
ECMAScript 5.1 (ECMA-262) The definition of 'ReferenceError' in that specification. |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'ReferenceError' in that specification. |
Standard | |
ECMAScript 2017 Draft (ECMA-262) The definition of 'ReferenceError' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
See also
License
© 2016 Mozilla 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