Extract CSSOM/DOM related utilities into a separate package

[kof]

As a first step of moving to jest, we need to separate the code that needs karma and cross-browser testing, since jest doesn't support that.

We can create a small functional utility belt for CSSinJS libraries that encapsulates all the CSSOM/DOM logic and we can use the current karma setup for this library.

Needed also for #745

[kof]

Should this package be part of the monorepo? I tend to "no" for 2 reasons:

• to make other libraries be more comfortable depending on it
• to not have karma setup with all its dependencies in this monorepo, since it would make bootstrapping longer

[HenriBeck]

Yeah, I would agree to not have karma and jest in this monorepo.

[kof]

Also if there is no easy way to setup karma with rollup, we could keep the current webpack config with karma in that separate repo, since it won't be often updated and neither its lots of code.

[HenriBeck]

Any idea for naming this package?

[kof]

cssinjs-utils is free

[kof]

mb cssom-utils is even better

[HenriBeck]

yeah cssom-utils is better

[HenriBeck]

@kof could you get started on this? That way we wouldn't need a separate test script for the babel plugin

[kof]

I want to finish babel and webpack plugins first. To kick start this we could discuss all functions that we would need to extract from JSS.

[HenriBeck]

I think the functions are mostly/all in https://github.com/cssinjs/jss/blob/master/packages/jss/src/renderers/DomRenderer.js

[kof]

Yes, but we will have to remove any JSS specific logic/knowledge from them to make them universal.