index.js
function _SubRange(low, high) {
    this.low = low;
    this.high = high;
    this.length = 1 + high - low;
}
function _SubRange(low, high) {
    this.low = low;
    this.high = high;
    this.length = 1 + high - low;
}
function _SubRange ( low , high ) { this . low = low ; this . high = high ; this . length = 1 + high - low ; }
protected helper class
protected helper class