CharCodeAt

charCodeAt is a method of the String object in JavaScript. It returns an integer between 0 and 65535 representing the UTF-16 code unit at the given index in the string. The index is zero-based, meaning the first character is at index 0, the second at index 1, and so on. If the index is out of range (less than 0 or greater than or equal to the string's length), charCodeAt returns NaN (Not a Number).

For example, if you have the string "hello", charCodeAt(0) would return the UTF-16 code unit for "h", which is 104. charCodeAt(1) would return the code unit for "e", which is 101, and so on.

This method is useful for various string manipulation tasks, such as comparing characters based on their underlying numerical representation, or when you need to work with the raw code units of a string. It's important to note that charCodeAt deals with UTF-16 code units, which might not directly correspond to Unicode code points for characters that require more than one UTF-16 code unit (surrogate pairs). For handling those cases, String.prototype.codePointAt is a more appropriate method.