Hi Mitch welcome to web dev!
So I can't say I'd recommend that workflow exactly, only because you don't want to have to write and rewrite code and make it into components.
Working with a designer myself we collaborate closely on a daily basis. If your designer is using sketch (which he loves) he can create wireframes and prototypes. Our workflow is similar to what you are proposing, this is what we do:
- We have a feature request that we need to design and build
- He creates a mockup / wireframe
- Then he whips that up into a prototype (optional)
- From there I turn the prototype into working code (we use angular)
- When I think I have recreated his prototype I ask him to look it over and we discuss from there.
For me, it is easy to go back and fix some CSS or change some HTML around, just keep everything organized and well commented so you can easily change stuff in the future as your app grows.
One other thing I would recommend is that you should create your own form of a wireframe so that you can see how your components are going to be placed and interacting with one another.
I hope that this helps you and your designer come up with a workflow that you both enjoy!