title: Migration path from legacy to webpack
body: <p>I have a single page application written in JavaScript ES5 and Angular 1.x, Twitter Bootstrap, UI Router, and several other dependencies. It currently has no modules and no build system and only minimal minification. All code just lives in the global namespace. </p>
  
  <p>The app started out as a prototype and having no build system was fine at first, but now its bigger and not having a proper build system starts to create all kinds of problems.</p>
  
  <p>I would like to transition this app to a webpack 2.x world, as that seems to be the most promising build system right now. But I do not really know where to start.</p>
  
  <p>Ideally I would like to do this gradually, such that I do not have to migrate all files at once.</p>
  
  <p>I have experimented with Webpack 1.x and 2.x for a while, and also created a small prototype that uses Angular 1.x, but I still do not see a way to do the migration step by step. It looks to me as if switching to webpack is an all-or-nothing decision.</p>