goja-core/src/main/java/goja/core/kits/lang/CharKit.java
protected static boolean isUnreserved(char c) {
        return isAlpha(c) || isDigit(c) || c == '-' || c == '.' || c == '_' || c == '~';
    }
protected static boolean isUnreserved(char c) {
        return isAlpha(c) || isDigit(c) || c == '-' || c == '.' || c == '_' || c == '~';
    }
Indicates whether the given character is in the <i>unreserved</i> set.

@see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>