This isn't to take away from the awesome work of the OP, but Google has a library of React UI components based on material design, and a similar time picker is one of them - http://www.material-ui.com/#/components/time-picker
Oh wow, I haven't noticed that. I somehow assumed that you wouldn't be putting Google in your tagline if you were not associated with the company. Shame on me.
I use Material UI for a few projects, and like it a lot. However, before you rely on it, you should be aware that certain components have pretty horrible performance pitfalls that aren't immediately obvious until you have a lot of components on the page (or a lot of updates); they seem to be addressing some of them, though.