backbone-find.js

// save a reference to $() method
var view$ = Backbone.View.prototype.$;

// then override it
Backbone.View.prototype.$ = function(selector) {
  var element = view$.apply(this, arguments);

  if (!element.length === 0) {
    console.error("[Backbone.View] Warning: selector '" + selector + "' do not match any element");
  }

  return element;
};