It appears that running the Draft.js website locally, depending on your dependency versions, will result in one of several broken states.
What we saw:
git clone of the Draft.js repository and following the instructions in https://github.com/facebook/draft-js/tree/master/website#run-the-server led to a high use of CPU and pages that were never loading - just blank.rm -rf node_moduels && rm yarn.lock inside /website and starting fresh, this error appeared: $ node server/server.js
module.js:529
throw err;
^
Error: Cannot find module 'react-page-middleware'
at Function.Module._resolveFilename (module.js:527:15)
at Function.Module._load (module.js:476:23)
at Module.require (module.js:568:17)
at require (internal/module.js:11:18)
at Object.<anonymous> (/Users/gmd/draft-js/website/server/server.js:13:23)
at Module._compile (module.js:624:30)
at Object.Module._extensions..js (module.js:635:10)
at Module.load (module.js:545:32)
at tryModuleLoad (module.js:508:12)
at Function.Module._load (module.js:500:3)
error Command failed with exit code 1.
I have found that installing react-page-middleware globally fixes this, for me. Here are my action items for this:
1) With a fresh environment and no global installation of react-page-middleware, what issues arise when running the docs site locally? Please comment here.
2) Let's set the version in the website/package.json for react-page-middleware to 0.4.1 and confirm that this works.
Thanks to @GordyD for surfacing this issue!
Maybe I'm missing something totally obvious but I've tried installing react-page-middleware globally and am encountering the same issue.
$ rm -rf ~/.config/yarn/global/node_modules/react-page-middleware/
$ ~/.config/yarn/global/node_modules/
$ yarn global add git://github.com/facebookarchive/react-page-middleware.git
Using globally installed version of Yarn
yarn global v1.2.0
warning package.json: No license field
[1/4] ๐ Resolving packages...
[2/4] ๐ Fetching packages...
[3/4] ๐ Linking dependencies...
[4/4] ๐ Building fresh packages...
warning "[email protected]" has no binaries
โจ Done in 2.50s.
$ ls ~/.config/yarn/global/node_modules/react-page-middleware/
LICENSE README.md node_modules package.json polyfill src
$ node
> const rp = require('react-page-middleware');
Error: Cannot find module 'react-page-middleware'
at Function.Module._resolveFilename (module.js:527:15)
at Function.Module._load (module.js:476:23)
at Module.require (module.js:568:17)
at require (internal/module.js:11:18)
at repl:1:12
at ContextifyScript.Script.runInThisContext (vm.js:50:33)
at REPLServer.defaultEval (repl.js:239:29)
at bound (domain.js:301:14)
at REPLServer.runBound [as eval] (domain.js:314:12)
at REPLServer.onLine (repl.js:440:10)
>
(To exit, press ^C again or type .exit)
>
N.B I'm able to require other globally installed npm modules through yarn so I don't think it is to do with system config.
I will give this a look. May not find a solution but can hopefully provide some more information from my perspective. ๐
Thanks @jackyho112 and @GordyD :)
I did a git clone, ran npm install at the root level of the freshly cloned project folder and then ran npm install again at the website folder. After all these steps, I did npm start at the website folder and was able to start the app fine.

Sorry, wasn't able to reproduce the issue.
Thanks! That is good news - I'm hoping that this was a corner case somehow triggered by @GordyD 's environment. Still would like to update the docs to a more modern tool but this makes it seem less urgent.
I believe that the migration to Docusaurus has fixed this issue. Please reopen if that is not the case :)
Most helpful comment
I will give this a look. May not find a solution but can hopefully provide some more information from my perspective. ๐