Since I was/am new to the language I had to figure out a lot of stuff including the tooling, the ecosystem, the syntax, the libraries. The documentation for Fable could be better. There are so many options for everything. I had to find a React library, a JSON library and figure out how to do HTTP requests. There were times where I almost gave up on the F#/Fable rewrite.
For archive purposes I've kept the original JS files in the source code so that I can compare the syntax and code in the future.