Move this into design notes

Author: faassen

TODO.md

@@ -64,14 +64,6 @@
 - Make typescript types for webxdc available as a standalone package so that
   developers can use this in their own projects.
 
-## Architecture
-
-- can we have only a single web socket that handles all frontends? We could
-  broadcast to all clients at once. The drawbacks of this are that the client
-  becomes dependent on more than just its own backend, and that we cannot
-  easily distinguish between instances and make one of them broken in some way.
-  It might also break CSP.
-
 ## Other
 
 - Update webxdc specification based on what I learned about it.

design-notes.md

@@ -1,5 +1,25 @@
-- I tried hard to make things work with Vite but had to go back to webpack to
-  gain the control I needed -- I need to be able to produce a frontend UI
-  bundle as well as the simulator `webxdc.js` bundle with a specific name. I
-  couldn't get Vite to support that. webpack provides the required control, at
-  the cost of more configuration.
+# Design notes
+
+## one websocket per instance
+
+Each instance has its own websocket it uses to communicate to the backend. It
+can be argued that only a single websocket is necessary that all instances use.
+This would allow a broadcast of messages to all clients at once.
+
+But there are drawbacks as the client becomes dependent on more than its own
+backend. This would require an exception in CSP, which is doable. More
+difficult is that the client would need to know which port to connect to, which
+would somehow need to be injected into `webxdc.js`. In the current architecture
+the client can easily talk to its own host without any further knowledge.
+
+## Webpack versus vite
+
+I tried hard to make things work with Vite as this was already in use with
+other projects within the webxdc org, but had to go to webpack to gain the
+control I needed -- I need to be able to produce a frontend UI bundle as well
+as the simulator `webxdc.js` bundle with a specific name. I couldn't get Vite
+to support that. webpack provides the required control, at the cost of more
+configuration.
+
+As an alternative I could have used `rollup` which should offer the control
+and is what vite itself uses.