Include Google Analytics and Segment initializers only once within the head section …

[nnande]

…of frontend layout view.

Currently initializer.js scripts both for GA and Segment can be included multiple times, once for each <meta> occurrence within a HTML page body (keyword, description, viewport, charset etc.)

Considering Segment integration, this can produce JS console errors (as can be seen below, there is a safeguard against such a case in the segment.js source code however still it's a good practice not to include obsolete JS snippets.

analytics.js source

<script type="text/javascript">
  (function(){
    ...
    // If the snippet was invoked already show an error.
    if (analytics.invoked) {
      if (window.console && console.error) {
        console.error('Segment snippet included twice.');
      }
      return;
    }
    ...    

I am not sure if some similar safeguard mechanism exists for Google Analytics.