Hot code reloading checklist

[rauchg]

Some example scenarios to check

• After making a change, server-rendering works as expected (bug)
• Errors render on the browser as well (with our existing style)
• Works with path registration / unregistration.
  • If I go to /test and test.js doesn't exist, render 404. Creating it renders test.js
  • If I create test.js but with an error, we replace the 404 with an error
  • If test.js has an error but I remove it, render 404
• Handle the scenario correctly where the user-created error.js has an error (fallback + console.error in main terminal is acceptable for this)
• Hot code reloading of error.js works when rendering an error

[nkzawa]

about rendering compilation errors, it can display syntax highlight which babel adds if we want.