RegExp.prototype.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 Language Specification (ECMAScript) # sec-get-regexp.prototype.source

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`source`	1	12	1	4	5	1	1	18	4	10.1	1	1.0
`empty_regex_string`	6	12	38	No	15	5	≤37	18	38	14	4.2	1.0
`escaping`	73	12	38	10	60	6	73	73	38	52	6	11.0
`prototype_accessor`	48	12	41	4	35	1.3	48	48	41	35	1	5.0