String.prototype.charAt()

The charAt() method of 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 String.prototype.codePointAt() and String.fromCodePoint().

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 codePointAt(i) and String.fromCodePoint() instead. For information on Unicode, see UTF-16 characters, Unicode code points, and grapheme clusters.

Syntax example: charAt(index)