The toString() method returns a string representing the specified Error object.

Syntax

e.toString()

Return value

A string representing the specified Error object.

Description

The Error object overrides the Object.prototype.toString() method inherited by all objects. Its semantics are as follows (assuming Object and String have their original values):

Error.prototype.toString = function() {
  'use strict';

  var obj = Object(this);
  if (obj !== this) {
    throw new TypeError();
  }

  var name = this.name;
  name = (name === undefined) ? 'Error' : String(name);

  var msg = this.message;
  msg = (msg === undefined) ? '' : String(msg);

  if (name === '') {
    return msg;
  }
  if (msg === '') {
    return name;
  }

  return name + ': ' + msg;
};

Examples

var e = new Error('fatal error');
console.log(e.toString()); // 'Error: fatal error'

e.name = undefined;
console.log(e.toString()); // 'Error: fatal error'

e.name = '';
console.log(e.toString()); // 'fatal error'

e.message = undefined;
console.log(e.toString()); // 'Error'

e.name = 'hello';
console.log(e.toString()); // 'hello'

Specifications

Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.1.
ECMAScript 5.1 (ECMA-262)
The definition of 'Error.prototype.toString' in that specification.
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Error.prototype.toString' in that specification.
Standard  
ECMAScript Latest Draft (ECMA-262)
The definition of 'Error.prototype.toString' in that specification.
Draft  

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung InternetNode.js
Basic supportChrome Full support YesEdge Full support YesFirefox Full support 1IE Full support 6Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yesnodejs Full support Yes

Legend

Full support  
Full support

See also

Document Tags and Contributors

Last updated by: fscholz,