Updated version of Angular ScrollSpy

scrollspy.coffee

angular.module('jobFoundryDirectives').directive 'spy', ($location) ->
  restrict: "A"
  require: "^scrollSpy"
  link: (scope, elem, attrs, scrollSpy) ->
    attrs.spyClass ?= "current"

    elem.click ->
      scope.$apply ->
        $location.hash(attrs.spy)

    scrollSpy.addSpy
      id: attrs.spy
      in: -> elem.addClass attrs.spyClass,
      out: -> elem.removeClass attrs.spyClass

angular.module('jobFoundryDirectives').directive 'scrollSpy', ($window) ->
  restrict: 'A'
  controller: ($scope) ->
    $scope.spies = []
    @addSpy = (spyObj) -> $scope.spies.push spyObj
  link: (scope, elem, attrs) ->
    spyElems = []
    
    scope.$watch 'spies', (spies) ->
      for spy in spies
        unless spyElems[spy.id]?
          spyElems[spy.id] = elem.find('#'+spy.id)

    $($window).scroll ->
      highlightSpy = null
      for spy in scope.spies
        spy.out()

        # the elem might not have been available when it was originally cached,
        # so we check again to get another element in case this one doesn't exist.
        spyElems[spy.id] =
          if spyElems[spy.id].length is 0
            elem.find('#'+spy.id)
          else
            spyElems[spy.id]

        # the element could still not exist, so we check first to avoid errors
        if spyElems[spy.id].length isnt 0
          if (pos = spyElems[spy.id].offset().top) - $window.scrollY <= 0
            spy.pos = pos
            highlightSpy ?= spy
            if highlightSpy.pos < spy.pos
              highlightSpy = spy

      highlightSpy?.in()

Thought I'd let you know that there is an issue with using $window.scrollY in Internet Explorer, it comes back as undefined. I know this cause i'm borrowing your code for a project i'm currently working on.
Found that if you use $window.pageYOffset then it will work in IE9+.
If you need IE8 as well then need to do something like $window.pageYOffset || $window.document.documentElement.scrollTop. Not sure what that code would be in coffeescript.

Breaks in Anguar 1.2.0 onwards. Adds unnecessary return, ln:20.

Line 18 to 20 should be

controller: ($scope) ->
  $scope.spies = []
  @addSpy = (spyObj) -> $scope.spies.push spyObj
  return

Otherwise, CoffeeScript implicitly returns this.appSpy()

If anyone is interested, I got this working for me, in JS, but it doesn't work within a ng-view(which was the purpose of this, making it work with dynamically added links?)

directive('scrollSpy', function($window) {
  return {
    restrict: 'A',
    controller: function($scope) {
      $scope.spies = [];
      $scope.test = 0;
      setTimeout(function(){console.log('$scope.test changed');$scope.test = 8}, 1000)
      this.addSpy = function(spyObj) {
        console.log('scroll added');
        $scope.spies.push(spyObj);
      };
    },
    link: function(scope, elem, attrs) {
      var spyElems = [];
      console.log(scope);
      scope.$watch('spies', function(spies) {
        console.log('$watch', spies);
        for (var _i = 0; _i < spies.length; _i++) {
          var spy = spies[_i];
          if (spyElems[spy.id] == null) {
            spyElems[spy.id] = (elem.find('#' + spy.id));
          }
        }
      }, true);

      $($window).scroll(function() {
        console.log(spyElems);
        var highlightSpy, pos, spy, _i, _len, _ref;
        highlightSpy = null;
        _ref = scope.spies;

        for (_i = 0, _len = _ref.length; _i < _len; _i++) {
          spy = _ref[_i];
          spy.out();
          console.log('spy',spy);
          spyElems[spy.id] = spyElems[spy.id].length === 0 ? elem.find('#' + spy.id) : spyElems[spy.id];
          if (spyElems[spy.id].length !== 0) {
            if ((pos = spyElems[spy.id].offset().top) - $window.scrollY <= 0) {
              spy.pos = pos;
              if (highlightSpy == null) {
                highlightSpy = spy;
              }
              if (highlightSpy.pos < spy.pos) {
                highlightSpy = spy;
              }
            }
          }
        }
        return highlightSpy != null ? highlightSpy["in"]() : void 0;
      });
    }
  };
}).
directive('spy', function($location) {
  return {
    restrict: "A",
    require: "^scrollSpy",
    link: function(scope, elem, attrs, scrollSpy) {
      console.log("scrollSpy," , scrollSpy);
      if (attrs.spyClass == null) {
        attrs.spyClass = "active";
      }
      elem.click(function() {
        scope.$apply(function() {
          $location.hash(attrs.spy);
        });
      });
      scrollSpy.addSpy({
        id: attrs.spy,
        in: function() {
          elem.addClass(attrs.spyClass);
        },
        out: function() {
          elem.removeClass(attrs.spyClass);
        }
      });
    }
  };
})

Hopefully this may be of help to someone, it uses a retry mechanism to check the element sizes before applying the scroll positions, this addressed this issue of unpredictable ng-view page rendering in my application.

http://plnkr.co/edit/MRKo8e?p=info

I did a JavaScript translation of this CoffeeScript and made a few updates. You can find the updates here: https://gist.github.com/EvilClosetMonkey/9194765

What changed:

1. Catch the case where a menu spy definition does not have an associated content id defined.
2. Select the last menu spy item if the browser is scrolled all the way to the bottom (content length sometimes prevent this from happening).
3. Changed the class to active to match Bootstrap's CSS.