These are notes for the stream implementation of Nodeplotlib.

General

A plot window (apps/web) tries to connect to the server via a realtime api (e.g. websockets).
The server recognizes the count of connected apps.
If the user executes the plot function several times, it will only open a window if there is no open connection to a apps/web.

Server lifecycle

The server starts with the execution of the plot function if there is no active server running.
The server stops if all apps/web are disconnected (and there were connections before).

The plot function can either handle a Plot or an Observable<Plot>.
- It creates an Observable<Plot> by using Rxjs' of observable constructor.
The plot streams are saved in a Plots Set.
If there is an active apps/web that listens to the server, it subscribes to all Plots in the Set.
It does not submit a whole "plots" object, but rather submits all plots one by one. The reason is realtime data, for which only the updated plot should be transmitted.
If all apps/web are disconnected, it should close the observable subscriptions of the plots and close the server as mentioned in the server lifecycle section.

Is the stack function really needed? Stack served the purpose that only one window opens which could display several plots.

The clear function is also probably not needed. Just close all windows and it should close the subscriptions to the plots and streams.

The user can remove plots from the frontend. If that happened it submits a message to the backend so that the subscription can be cancelled and the plot stream can be removed from the plots set.

To start the app for development purposes run

npm run build web -- --watch
npm start dev-server