I’ve long been a fan of MixPanel and was happy that I got to get to use them again over at Wave Payroll. Last time I used them you could only track a page view, but now they have added track_links and track_forms which fire the event asynchronously after the link is clicked or the form is submitted.

I started off by using the event_tracker gem which only handles the page view events, but it does make it easier to fire events in the view based on controller actions so it is well worth using. I talked to the author about adding support for track_links and track_forms, but after a good discussion he convinced me that the gem was not the right place for this and that I should pursue something more elegant such as tagging the links.

Ideally, what we wanted to arrive at was something like

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<a href="blah" class="track-with-mixpanel" data-event="clicked on login">

or with Rails helpers:

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=link_to login_path, :class => "track-with-mixpanel", :data => { :event => "clicked on login" }

which would magically call

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mixpanel.track_links("#id_of_element", "clicked on login")

One problem is that not all the elements had IDs and I didn’t want the added friction of having to add that in.

What I came up with was:

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$(".track-with-mixpanel").each( function(i) {
  var obj = $(this);
  // Make up an ID if there is none
  if (!obj.attr('id')) {
    obj.attr('id', "mixpanel" + Math.floor(Math.random() * 4294967296));
  }
  if (obj.is("form")) {
    mixpanel.track_forms("#" + obj.attr("id"), obj.data('event'), obj.data('properties'));
  } else {
    mixpanel.track_links("#" + obj.attr("id"), obj.data('event'), obj.data('properties'));
  }
});

So this simply finds all the links with the track-with-mixpanel class, assigns them a random ID if they don’t have one, and then calls the appropriate mixpanel function on them.

A couple of notes, though…

The first is that the data-properties doesn’t quite work right. Pulling the data into a hash requires some finesse that I haven’t been able to figure out.

The second is that track_links and track_forms are horribly broken and will mess up any onClick handlers you have. So if you have links that you use :method => :post for, some third party javascript like validations or Stripe, you’re better off with the old track method because Mixpanel won’t play nicely with it. But for regular links and forms, this is great.