The toString() method returns a string representing the regular expression.
regexObj.toString();
A string representing the given object.
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.
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'
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
| 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 |
| Desktop | ||||||
|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | |
| Basic support | Yes | Yes | 1 | Yes | Yes | Yes |
| Escaping | Yes | Yes | 38 | Yes | Yes | Yes |
| Generic function | ? | ? | 39 | ? | ? | ? |
| Mobile | |||||||
|---|---|---|---|---|---|---|---|
| Android webview | Chrome for Android | Edge Mobile | Firefox for Android | Opera for Android | iOS Safari | Samsung Internet | |
| Basic support | Yes | Yes | Yes | 4 | Yes | Yes | Yes |
| Escaping | Yes | Yes | Yes | 38 | Yes | Yes | Yes |
| Generic function | ? | ? | ? | 39 | ? | ? | ? |
| Server | |
|---|---|
| Node.js | |
| Basic support | Yes |
| Escaping | Yes |
| Generic function | ? |
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/toString