getting a string length that contains unicode character exceeding 0xffff

Question

I’m using this character, double sharp \'

Answer 1

That's the function I wrote to get string length in codepoint length

function nbUnicodeLength(string){
    var stringIndex = 0;
    var unicodeIndex = 0;
    var length = string.length;
    var second;
    var first;
    while (stringIndex < length) {

        first = string.charCodeAt(stringIndex);  // returns an integer between 0 and 65535 representing the UTF-16 code unit at the given index.
        if (first >= 0xD800 && first <= 0xDBFF && string.length > stringIndex + 1) {
            second = string.charCodeAt(stringIndex + 1);
            if (second >= 0xDC00 && second <= 0xDFFF) {
                stringIndex += 2;
            } else {
                stringIndex += 1;
            }
        } else {
            stringIndex += 1;
        }

        unicodeIndex += 1;
    }
    return unicodeIndex;
}