Web/JavaScript/Reference/Global objects/RegExp/source

The source property returns a String containing the source text of the regexp object, and it doesn't contain the two forward slashes on both sides and any flags.

Property attributes of `RegExp.prototype.source`
Writable	no
Enumerable	no
Configurable	yes

Examples

Using source

var regex = /fooBar/ig;

console.log(regex.source); // "fooBar", doesn't contain /.../ and "ig".

Empty regular expressions and escaping

Starting with ECMAScript 5, the source property no longer returns an empty string for empty regular expressions. Instead, the string (?:) is returned. In addition, line terminators (such as "\n") are escaped now.

new RegExp().source; // "(?:)"

new RegExp('\n').source === '\n';  // true, prior to ES5
new RegExp('\n').source === '\\n'; // true, starting with ES5

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'RegExp.prototype.source' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`source`	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 4	Opera Full support 5	Safari Full support 1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0	nodejs Full support 0.1.100
"(?:)" for empty regexps	Chrome Full support 6	Edge Full support 12	Firefox Full support 38	IE No support No	Opera Full support 15	Safari Full support 5	WebView Android Full support ≤37	Chrome Android Full support 18	Firefox Android Full support 38	Opera Android Full support 14	Safari iOS Full support 4.2	Samsung Internet Android Full support 1.0	nodejs Full support 0.8.0
Escaping	Chrome Full support 73	Edge Full support 12	Firefox Full support 38	IE Full support 10	Opera Full support 60	Safari Full support 6	WebView Android Full support 73	Chrome Android Full support 73	Firefox Android Full support 38	Opera Android Full support 52	Safari iOS Full support 6	Samsung Internet Android No support No	nodejs Full support 12.0.0
Prototype accessor property (ES2015)	Chrome Full support 48	Edge Full support 12	Firefox Full support 41	IE Full support 4	Opera Full support 35	Safari Full support 1.3	WebView Android Full support 48	Chrome Android Full support 48	Firefox Android Full support 41	Opera Android Full support 35	Safari iOS Full support 1	Samsung Internet Android Full support 5.0	nodejs Full support 6.0.0

Legend

Full support: Full support
No support: No support