It's unfortunate that people still think they need monolithic libraries to get anything done on the client side. The node ecosystem showed this doesn't have to be the case. It becomes even more important on the client side to keep dependencies small.
My favourite ecosystem for client side development these days is component (https://github.com/component/component). It's similar in style to npm but faster and made for building apps from small modular pieces. It has a growing community and lots of modules already (https://github.com/component/component/wiki/Components).