The toString()
method returns a string representing the regular expression.
Syntax
regexObj.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:
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:
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 Latest Draft (ECMA-262) The definition of 'RegExp.prototype.toString' in that specification. |
Draft |
Browser compatibility
See also
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