Encode non-printable characters as hex

encodeNP.js

var encodeNP = function(s){
    var hex, c;
    var result = '';
    for (var i = 0; i < s.length; i++) {
        c = s.charCodeAt(i);
        if (c >= 32 && c <= 126) {
            result += String.fromCharCode(c);
        } else {
            hex = c.toString(16);
            result += '\\x' + ('000'+hex).slice(-4);
        }
    }

    return result;
}