Javascript and Initializers

DEV has two Javascript codebases.

One is located in the directory app/assets/javascripts and contains plain Javascript (mostly ES5+) being served using Sprockets which packages static assets.

Webpacker manages the other one, and you can read more about in its own guide.

This source code is not transpiled, only packaged and minified, and will be limited to whatever flavour of Javascript can run on the user's web browser.

app/assets/javascripts/application.js contains the manifest Javascript file which is included globally in the primary template, app/views/layouts/application.html.erb.

application.js automatically includes all JS files via the statement:

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//= require_tree .

One JS file in particular, app/assets/javascripts/initializePage.js.erb, boostraps the majority of the functionality. You will notice, within this file, that major sections of the websites are bootstrapped, for example:

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initializeBaseTracking();
initializeTouchDevice();
initializeCommentsPage();
initEditorResize();
initLeaveEditorWarning();
initializeArticleReactions();
initNotifications();
initializeSplitTestTracking();

All the "initializers" are in /app/assets/javascripts/initializers.