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    Error.prototype.toString()

    Summary

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

    Syntax

    e.toString()

    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');
    print(e.toString()); // 'Error: fatal error'
    
    e.name = undefined;
    print(e.toString()); // 'Error: fatal error'
    
    e.name = '';
    print(e.toString()); // 'fatal error'
    
    e.message = undefined;
    print(e.toString()); // 'Error'
    
    e.name = 'hello';
    print(e.toString()); // 'hello'
    

    Specifications

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

    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

    Document Tags and Contributors

    Contributors to this page: evilpie, Sheppy, fscholz, Mingun, Sevenspade, ethertank, getify, Waldo
    Last updated by: Mingun,