The code is on GitHub: https://github.com/vman/Edit-User-Properties
Since I had not worked with React a lot, I decided to choose it as my JS framework.
Things I managed to wrap my head around while creating this simple webpart:
1) How to create a SPFx webpart with React as the JS framework.
2) How to talk to SharePoint from within the SPFx webpart with context.httpClient.get and context.httpClient.post
4) Creating reactive as well as non reactive webpart properties
5) The new _spClientSidePageContext object which contains heaps of context data. According to the wiki, properties of this object will be deprecated and moved under the Context object of the webpart.
(For now, I had to manually create an ambient declaration for this object but hopefully soon, the need for this will go away as it will be moved in the Context object)
6) Office UI Fabric and React Components for Office UI fabric
Since lots of these things were new to me, you might find some bugs/mistakes/horrors in the code so apologies for that in advance. Don't forget to leave a comment and I will be happy to update my code.