Navigation highlighting for one page website

nav.js

(function() {
  var Nav;

  Nav = (function() {

    function Nav(selector) {
      this.selector = selector;
      this.element = $(this.selector || "[data-nav]").first();
      this["class"] = this.element.data("nav");
      this.height = this.element.parent().height();
      this.links = this.element.find("a");
      this.link = null;
      this.offsets = $.map(this.links, function(link) {
        return $($(link).attr("href")).offset().top;
      });
      this.onScroll();
      this.bindEvents();
    }

    Nav.prototype.bindEvents = function() {
      return $(document).on("scroll", $.proxy(this.onScroll, this));
    };

    Nav.prototype.onScroll = function() {
      var currentLink, scrolled,
        _this = this;
      scrolled = $(document).scrollTop();
      this.link = this.links.first();
      $.each(this.offsets, function(index, offset) {
        if (offset < (scrolled + _this.height)) {
          return _this.link = _this.links.get(index);
        }
      });
      currentLink = $(this.link);
      if (!currentLink.hasClass(this["class"])) {
        $("." + this["class"]).removeClass(this["class"]);
        return currentLink.addClass(this["class"]);
      }
    };

    return Nav;

  })();

  window.Nav = Nav;

}).call(this);