RegExp.prototype.toString()

The toString() method of {{jsxref("RegExp")}} instances returns a string representing this regular expression.

{{InteractiveExample("JavaScript Demo: RegExp.prototype.toString()", "taller")}}

```js interactive-example console.log(new RegExp("a+b+c")); // Expected output: /a+b+c/

console.log(new RegExp("a+b+c").toString()); // Expected output: "/a+b+c/"

console.log(new RegExp("bar", "g").toString()); // Expected output: "/bar/g"

console.log(new RegExp("\n", "g").toString()); // Expected output: "/\n/g"

console.log(new RegExp("\n", "g").toString()); // Expected output: "/\n/g"

## Syntax

```js-nolint
toString()

Parameters#

None.

Return value#

A string representing the given object.

Description#

The {{jsxref("RegExp")}} object overrides the toString() method of the {{jsxref("Object")}} object; it does not inherit {{jsxref("Object.prototype.toString()")}}. For {{jsxref("RegExp")}} objects, the toString() method returns a string representation of the regular expression.

In practice, it reads the regex's source and flags properties and returns a string in the form /source/flags. The toString() return value is guaranteed to be a parsable regex literal, although it may not be the exact same text as what was originally specified for the regex (for example, the flags may be reordered).

Examples#

Using toString()#

The following example displays the string value of a {{jsxref("RegExp")}} object:

const myExp = new RegExp("a+b+c");
console.log(myExp.toString()); // '/a+b+c/'

const foo = new RegExp("bar", "g");
console.log(foo.toString()); // '/bar/g'

Empty regular expressions and escaping#

Since toString() accesses the source property, an empty regular expression returns the string "/(?:)/", and line terminators such as \n are escaped. This makes the returned value always a valid regex literal.

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

new RegExp("\n").toString() === "/\\n/"; // true

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Object.prototype.toString()")}}