What is a surrogate pair?

Question

I came across this code in a javascript open source project.

validator.isLength = function (str, min, max) 
    // match surrogate pairs in string or declare         


        

Answer 1

1. Yes. Your understanding is correct. The function returns the length of the string in Unicode Code Points.

2. JavaScript is using UTF-16 to encode its strings. This means two bytes (16-bit) are used to represent one Unicode Code Point.

   Now there are characters (like the Emojis) in Unicode that have a that high code point so that they cannot be stored in 2 bytes (16bit) so they need to get encoded into two UTF-16 characters (4 bytes). These are called surrogate pairs.

Try this

var len = "