[JS]글자 Byte계산, Byte자르기

getByteLength: function(string) {
    if (string == null || string.length == 0) {
        return 0;
    }
    let size = 0;
    for (let idx in string.length) {
        size += this.charByteSize(string.charAt(idx));
    }
    return size;
}

charByteSize: function(ch) {
    if (ch == null || ch.length == 0) {
        return 0;
    }
    let charCode = ch.charCodeAt(0);
    if (charCode <= 0x00007F) {
        return 1;
    } else if (charCode <= 0x0007FF) {
        return 2;
    } else if (charCode <= 0x00FFFF) {
        return 3;
    } else {
        return 4;
    }
}

String 을 받아서 Byte를 계산하여 Return

cutByteLength: function(string, length) {
    if (string == null || string.length == 0) {
        return 0;
    }
    let size = 0;
    let rIndex = string.length;

    for (let idx in string.length) {
        size += this.charByteSize(string.charAt(idx));
        if (size == length) {
            rIndex = i + 1;
            break;
        } else if (size > length) {
            rIndex = i;
            break;
        }
    }
    return string.substring(0, rIndex);
}​

String 을 받아서 특정 Byte를 넘으면 글자 자르기