How to make `pub build` pick up javascript & css files from packages

Question

Using pub build will pick up packages/browser/dart.js but it won't pick up javascript files included from other libraries. How can you make pub build pick up those external javascript & css files?

Answer 1

You should put that files in assets.

On a discussion about Assets-only Pub Packages Bob Nystrom gave some explaination about browser package and pub build:

It has some gross special-case code to handle the JS files in the browser package. That's been in there since before the idea of an "asset" directory existed, and it got Grandfathered in.