String.prototype.toString()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The toString() method of String values returns this string value.

Try it

Syntax

js
toString()

Parameters

None.

Return value

A string representing the specified string value.

Description

The String object overrides the toString method of Object; it does not inherit Object.prototype.toString(). For String values, the toString method returns the string itself (if it's a primitive) or the string that the String object wraps. It has the exact same implementation as String.prototype.valueOf().

The toString() method requires its this value to be a String primitive or wrapper object. It throws a TypeError for other this values without attempting to coerce them to string values.

Because String doesn't have a [Symbol.toPrimitive]() method, JavaScript calls the toString() method automatically when a String object is used in a context expecting a string, such as in a template literal. However, String primitive values do not consult the toString() method to be coerced to strings — since they are already strings, no conversion is performed.

js
String.prototype.toString = () => "Overridden";
console.log(`${"foo"}`); // "foo"
console.log(`${new String("foo")}`); // "Overridden"

Examples

Using toString()

The following example displays the string value of a String object:

js
const x = new String("Hello world");

console.log(x.toString()); // "Hello world"

Specifications

Specification
ECMAScript Language Specification
# sec-string.prototype.tostring

Browser compatibility

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See also