RegExp.prototype.toString()
The toString()
method returns a string representing the regular expression.
Syntax
JavaScript
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<var>regexObj</var>.toString();
Return value
A string representing the given object.
Description
The RegExp
object overrides the toString()
method of the Object
object; it does not inherit Object.prototype.toString()
. For RegExp
objects, the toString()
method returns a string representation of the regular expression.
Examples
Using toString()
The following example displays the string value of a RegExp
object:
JavaScript
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var myExp = new RegExp('a+b+c'); console.log(myExp.toString()); // logs '/a+b+c/' var foo = new RegExp('bar', 'g'); console.log(foo.toString()); // logs '/bar/g'
Empty regular expressions and escaping
Starting with ECMAScript 5, an empty regular expression returns the string "/(?:)/" and line terminators such as "\n" are escaped:
JavaScript
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new RegExp().toString(); // "/(?:)/" new RegExp('\n').toString() === "/\n/"; // true, prior to ES5 new RegExp('\n').toString() === "/\\n/"; // true, starting with ES5
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.1. |
ECMAScript 5.1 (ECMA-262) The definition of 'RegExp.prototype.toString' in that specification. |
Standard | Added definition for escaping behavior and "(?:)" for empty regular expressions. |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'RegExp.prototype.toString' in that specification. |
Standard | |
ECMAScript 2017 Draft (ECMA-262) The definition of 'RegExp.prototype.toString' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Escaping | (Yes) | 38 (38) | (Yes) | (Yes) | (Yes) |
Generic function | ? | 39 (39) | ? | ? | ? |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Escaping | (Yes) | (Yes) | 38.0 (38) | (Yes) | (Yes) | (Yes) |
Generic function | ? | ? | 39.0 (39) | ? | ? | ? |
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/regexp/tostring