npm run build fails

[rickhurkens]

npm run build fails for me with this message:

spotify-to-youtube/node_modules/bs-node-http-server/src/httpServer.re", line 4, characters 28-31:
Error: Unclosed "{" (opened line 2, column 4)

  We've found a bug for you!
  /Users/Rick/_mystuff/Projects_current/spotify-youtube-downloader/spotify-to-youtube/node_modules/bs-node-http-server/src/httpServer.re
  
  There's been an error running Reason's parser on a file.
  If the message doesn't help, check for errors slightly above.
  Please file an issue on github.com/facebook/reason. Thanks!
  
FAILED: subcommand failed.

I have tried to examine the file. However, I don't understand this language at all. I have removed the '.' that sits behind the '{', but that didn't work. "bs-node-http-server" does not have another version to try.