Integration with google analytics or other analytics

I think the question here is also how to use drupal_add_js() to add the callback.

 if (module_exists('disqus')) {
    drupal_add_js(array('disqus' => array('callbacks' => array('onNewComment' => "function(){ _gas.push(['_trackEvent','Blog','New Comment',window.location.href]); }"))), 'setting');
  }

something like that should work, right?

I have the same request and I think the best approach would be to implement the callback in a #post_render to the 'disqus' element. I've attached a patch that does this in a module called disqus_ga which I'm hoping can be a submodule to Disqus.

Other modules that want to do something different on the callback can either override the js callback using hook_js_alter() or follow the logic of the module to add their own callback.

Your patch looks like a whole new module. Did you want to include it in Disqus integration or create a standalone plugin?

I thought it would benefit everybody if it was a submodule of Disqus. What do you think?

That would work, but we need a patch against module for that also.

I thought this patch would work. Works for me. Is there something I need to follow? Could you point me in the right direction please? Thank you.

Here is the patch which is going to integrate the GA Tracking without creating a sub-mudule as in my opinion having a separate module for that is superfluous.
Things to mention:
- This patch will support the both, the old GA api and the new analytics.js and Universal Analytics (see: https://developers.google.com/analytics/devguides/collection/upgrade/ref... ).
Inspired from http://cgit.drupalcode.org/google_analytics_et/tree/js/google_analytics_... ;
- As we have already 3 .js files it's worth to move theme in a separate directory "js";

Please review.

Thank you for your work. Looks very good. I'd suggest just few simple cosmetic improvements:

1. +++ b/disqus.admin.inc
   @@ -97,6 +97,12 @@ function disqus_admin_settings() {
   +    '#default_value' => variable_get('disqus_track_newcomment_ga', FALSE),
   +  );
   

   Let's add this new configuration variable to the hook_uninstall().

2. +++ b/js/disqus_ga.js
   @@ -0,0 +1,36 @@
   +  };
   +
   +})(jQuery);
   \ No newline at end of file
    
   

   Missing newline.

3. It would be great to mention this new feature in README.txt too

It would be great to get this into 8.x-1.x first.

Thanks for the improvements suggestion.
Attaching the improved patch for 7.x-1.x (I also changed the callback name to make it more descriptive).
In the main time I'll work on 8.x-1.x branch.

I saw that variable deletion is sorted alphabetically - pushing new variable in the corespondent place :)

Here is the patch for 8.x-1.x

JS file seems to be missing in D8 patch.

@hugronaphor: Check https://www.drupal.org/documentation/git/interdiff. Interdiffs are great way to clearly show changes between individual patches and make it much easier for people to review your work.

Here is the fixed patch with js file included and interdiff.
Thanks for pointing me into the right direction.

Thanks! This looks great. I missed another critical and another cosmetic thing during my last review. I apologize for ping-pong....

+++ b/src/Element/Disqus.php
@@ -60,6 +60,14 @@ class Disqus extends RenderElement {
+    if (\Drupal::config('disqus.settings')->get('behavior.disqus_track_newcomment_ga')) {
+      // Add a callback when a new comment is posted.
+      $disqus['callbacks']['onNewComment'][] = 'disqusTrackNewComment';
+      // Attach the js with the callback implementation.
+      $element['#attached']['library'][] = 'disqus/disqus_ga';
+    }

Library name is actually "disqus/disqus". However, since GA integraton can be disabled it would be nicer to separate it's JS into a separate library (which could be called "disqus/ga" eventually).

See https://www.drupal.org/node/2201089 for more info about libraries and their definition.

+++ b/js/disqus_ga.js
@@ -0,0 +1,38 @@
+disqusTrackNewComment = function() {
+

Would be nice to have this function namespaced in "Drupal.disqus". This applies to D7 too.

Before uploading the patch, would this be the correct way? :
disqus.libraries.yml

disqus:
  version: 1.x
  js:
    js/disqus.js: {}
    js/disqus_ga.js: {}
    js/disqus.settings.js: {}
  dependencies:
    - core/jquery
    - core/jquery.once
    - core/drupal
ga:
  version: 1.x
  js:
    js/disqus_ga.js: {}
  dependencies:
    - disqus/disqus

And I'm not sure I understand the meaning of "Drupal.disqus" namespace.
Do you mean as Drupal behavior maybe:

Drupal.behaviors.disqusTrackNewComment = {
  attach: function(context, settings) {
    // ...
  }
};

?

1. That looks ok.
2. No, I don't mean behaviours. They have a very specific meaning. I mean defining function inside Drupal.disqus subdocument instead on a global level. It is a good practice and part of Drupal's JS coding standards too. Check how it is done in Entity browser (http://cgit.drupalcode.org/entity_browser/tree/js/entity_browser.iframe....). You can also check appropriate part of coding standards doc (https://www.drupal.org/node/172169#functions).

This Issue can't be solved until the https://www.drupal.org/node/2476065 is not merged into 8.x-1.x

#2476065 was merged.

Thanks @slashrsm
Here is the latest patch against 8.x-1.x

Committed. Thank you!

Now we can include this in D7 version too.

Here is the last path against the 7.x-1.x

Even if you suggested to namespace the function disqusTrackNewComment in "Drupal.disqus" namespace - I found it a bit difficult to manage the order of added JS files as we did in D8 branch (by using the libraries "dependenctcies" property) and this may create problems in future.

There are no other JS functions using this namespace at the moment so this would not be a problem, right?

Correct, there are no other JS functions using this namespace.
I'm concerned about where to declare the Drupal.disqus = {}; to make sure this will be available in any other part of APP. But you never can be sure without checking if the object exist already (this what I'm trying to avoid).

For now we could declare it in this file and try to fix this problem when we face it.

I see what you mean. Here it is.

Committed. Thanks!