String.prototype.charAt()

The charAt() method of {{jsxref("String")}} values returns a new string consisting of the single UTF-16 code unit at the given index.

charAt() always indexes the string as a sequence of UTF-16 code units, so it may return lone surrogates. To get the full Unicode code point at the given index, use {{jsxref("String.prototype.codePointAt()")}} and {{jsxref("String.fromCodePoint()")}}.

{{InteractiveExample("JavaScript Demo: String.prototype.charAt()", "shorter")}}

```js interactive-example const sentence = "The quick brown fox jumps over the lazy dog.";

const index = 4;

console.log(The character at index ${index} is ${sentence.charAt(index)}); // Expected output: "The character at index 4 is q"

## Syntax

```js-nolint
charAt(index)

Parameters#

• index
• : Zero-based index of the character to be returned. Converted to an integer — undefined is converted to 0.

Return value#

A string representing the character (exactly one UTF-16 code unit) at the specified index. If index is out of the range of 0 – str.length - 1, charAt() returns an empty string.

Description#

Characters in a string are indexed from left to right. The index of the first character is 0, and the index of the last character in a string called str is str.length - 1.

Unicode code points range from 0 to 1114111 (0x10FFFF). charAt() always returns a character whose value is less than 65536, because the higher code points are represented by a pair of 16-bit surrogate pseudo-characters. Therefore, in order to get a full character with value greater than 65535, it is necessary to retrieve not only charAt(i), but also charAt(i + 1) (as if manipulating a string with two characters), or to use {{jsxref("String/codePointAt", "codePointAt(i)")}} and {{jsxref("String.fromCodePoint()")}} instead. For information on Unicode, see UTF-16 characters, Unicode code points, and grapheme clusters.

charAt() is very similar to using bracket notation to access a character at the specified index. The main differences are:

• charAt() attempts to convert index to an integer, while bracket notation does not, and directly uses index as a property name.
• charAt() returns an empty string if index is out of range, while bracket notation returns undefined.

Examples#

Using charAt()#

The following example displays characters at different locations in the string "Brave new world":

const anyString = "Brave new world";
console.log(`The character at index 0   is '${anyString.charAt()}'`);
// No index was provided, used 0 as default

console.log(`The character at index 0   is '${anyString.charAt(0)}'`);
console.log(`The character at index 1   is '${anyString.charAt(1)}'`);
console.log(`The character at index 2   is '${anyString.charAt(2)}'`);
console.log(`The character at index 3   is '${anyString.charAt(3)}'`);
console.log(`The character at index 4   is '${anyString.charAt(4)}'`);
console.log(`The character at index 999 is '${anyString.charAt(999)}'`);

These lines display the following:

The character at index 0   is 'B'

The character at index 0   is 'B'
The character at index 1   is 'r'
The character at index 2   is 'a'
The character at index 3   is 'v'
The character at index 4   is 'e'
The character at index 999 is ''

charAt() may return lone surrogates, which are not valid Unicode characters.

const str = "𠮷𠮾";
console.log(str.charAt(0)); // "\ud842", which is not a valid Unicode character
console.log(str.charAt(1)); // "\udfb7", which is not a valid Unicode character

To get the full Unicode code point at the given index, use an indexing method that splits by Unicode code points, such as {{jsxref("String.prototype.codePointAt()")}} and spreading strings into an array of Unicode code points.

const str = "𠮷𠮾";
console.log(String.fromCodePoint(str.codePointAt(0))); // "𠮷"
console.log([...str][0]); // "𠮷"

[!NOTE] Avoid re-implementing the solutions above using charAt(). The detection of lone surrogates and their pairing is complex, and built-in APIs may be more performant as they directly use the internal representation of the string. Install a polyfill for the APIs mentioned above if necessary.

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("String.prototype.indexOf()")}}
• {{jsxref("String.prototype.lastIndexOf()")}}
• {{jsxref("String.prototype.charCodeAt()")}}
• {{jsxref("String.prototype.codePointAt()")}}
• {{jsxref("String.prototype.split()")}}
• {{jsxref("String.fromCodePoint()")}}
• JavaScript has a Unicode problem by Mathias Bynens (2013)