charAt vs charCodeAt?

Question

JavaScript provides charAt and charCodeAt methods on strings.

• What is the difference between these two methods?
• When would one use on over the other?

Answer 1

From the MDN page on charAt

The String object's charAt() method returns a new string consisting of the single UTF-16 code unit located at the specified offset into the string.

From the MDN page on charCodeAt:

The charCodeAt() method returns an integer between 0 and 65535 representing the UTF-16 code unit at the given index.

The UTF-16 code unit matches the Unicode code point for code points which can be represented in a single UTF-16 code unit. If the Unicode code point cannot be represented in a single UTF-16 code unit (because its value is greater than 0xFFFF) then the code unit returned will be the first part of a surrogate pair for the code point. If you want the entire code point value, use codePointAt().

• If you need the char as a string, call charAt.

• If, for some reason, you need the UTF char code, call charCodeAt

  (You could use it to increment the character for example.)

Answer 2

var a = 'ABC.................Z';
a.charCodeAt(0); // will return 65
a.charAt(0); // will return 'A'