Do you use Bundling and/or AMD
AMD and RequireJs
Pro: Only the js modules you need are downloaded
Con: Each module is downloaded in a separate http request
Bundling and Minification
This is a server side technique that combines and optimises client side files into single, optimised downloads.
ASP.Net contains excellent server-side bundling support as outlined here: http://www.asp.net/mvc/overview/performance/bundling-and-minification
ASP.Net vnext & VS 2015 also provides support for using task runners like Gulp or Grunt for bundling and minification.
Pro: Fewer Http requests and smaller files
Con: All client side modules are included in a single download