How It Works

Essentially Webpack builds the app into two bundles, one for the server and one for the client. These are dropped into the /meteor_core folder on every change.

To speed this up in development mode, it's actually streaming the changes via Webpack Dev Server and patches in just the files that changed. This makes things very fast and allows for better caching. However, you can still conceptually think of Webpack dropping the new bundle in on every change.