Overriding Backbone Constructor.

backboneConstructor.js

Backbone.View.extend({
  constructor: function (options) {
    // Do stuff before the View has been setup
    
    Backbone.View.apply(this, arguments);
    
    // Do stuff after the View has been setup,
    // particularly after `initialize()` has been called

    return this;
  }
});

also technically this is just extending the constructor, you are not overriding it because you are calling the original constructor