Error.prototype.toString()
The toString()
method returns a string representing the specified Error
object.
Syntax
JavaScript
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<var>e</var>.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):
JavaScript
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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
JavaScript
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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 2017 Draft (ECMA-262) The definition of 'Error.prototype.toString' 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/error/tostring