Backbone constructor override.

backbone-constructor.js

;['View'
, 'Model'
, 'Collection'
, 'Router'
].forEach(function(klass) {
  var original = Backbone[klass]
  Backbone[klass] = original.extend({
    constructor: function() {
      // Custom logic here...
      return original.apply(this, arguments);
    }
  });
});