Allow configuring ga tracker name when enabling ga analytics for Prebid

[bborn]

See issue #291

[mkendall07]

Thanks for the PR @bborn
Do you know the way to get the tracker name from GTM? Since they append a timestamp to their object name, it would be hard to know it ahead of time (to pass through the ga.config object). Any thoughts there?

[bborn]

Yeah, docs are here: https://developers.google.com/analytics/devguides/collection/analyticsjs/accessing-trackers#getall

ga(function(tracker) {
  // Logs the trackers name.
  // (Note: default trackers are given the name "t0")
  console.log(tracker.get('name'));

  // Logs the client ID for the current user.
  console.log(tracker.get('clientId'));

  // Logs the URL of the referring site (if available).
  console.log(tracker.get('referrer'));
});

I'm pretty sure GTM also logs the timestamp to the dataLayer, but I didn't figure out exactly where/when.

I don't think Prebid should do that though - there are cases where a uses might have set there own custom name, or where there are multiple trackers on the page (so how would Prebid know which one to use?). I think it makes more sense to just allow setting the name and then let the user pass it in (and maybe give an example of usage with GTM).

[mkendall07]

This else isn't necessary, since it's already defined as null

[mkendall07]

@bborn
Thanks for the commits and PR. I've updated with my feedback, can you please address those, and squash your commits into a single commit (http://gitready.com/advanced/2009/02/10/squashing-commits-with-rebase.html) then force commit

[bborn]

@mkendall07 ok, does this look better? I'm a little out of my element here (JS/node), but I think setting a _trackerPrefix variable makes more sense, since the prefix is composed of the trackerName plus a .

[mkendall07]

This doesn't need to be a function. Just do exports.prefixedSend = _trackerPrefix + 'send';

[bborn]

Does that exports.prefixedSend need to be inside the enableAnalytics function?

[bborn]

@mkendall07 updated to use trackerSend. It also seems like all those window[_gaGlobal]( trackerSend, 'event' calls should be refactored to use a function, but I didn't want to mess with it.

[protonate]

Thanks, could you flatten these two commits? And then we'll be ready to merge.

[bborn]

Done.

[protonate]

trackerSend is undefined when this function is called, you probably want a local variable for it. Also the test needs to be updated with the exported trackerSend -- though I believe that is the only case where the export is needed?

[bborn]

@protonate not sure how that happens. Shouldn't enableAnalytics always get called before this function, therefore setting trackerSend?

[protonate]

trackerSend is defined on the options object at line 42, it's not accessible any other way at the moment. The window[_gaGlobal] function is called when the _analyticsQueue is iterated in the checkAnalytics function, so scope has changed a few times over by this point. I've attached two screenshots that illustrate this.

This could be made to work by declaring trackerSend as a local variable in the ga module's scope, as you do with _trackerPrefix. Then it will be accessible to enableAnalytics and all the sendToGa functions.

[bborn]

Sorry - fixed specs.

[protonate]

Fixed undefined error and merged manually with this commit: 3551d9e

Thanks for contributing to Prebid.js.