[dev-approuter] Allow to start CAP server with cds-ts serve or any other command

[tiosteel]

Is your feature request related to a problem? Please describe.
I want to use the dev-approuter in combination with monorepo and TS on both SAPUI5 and CAP sides for local development.

I'm almost there:
https://github.com/tiosteel/mortgagecalc
(see srv/cap-server and app/router)

The only thing which prevents me from finalising it is a fact that dev-approuter cannot start my server with cds-ts serve.

Describe the solution you'd like
a. allow to provide a console command to start CAP server
b. allow to specify if I need the exact cds-ts to start it

Describe alternatives you've considered
a. Use regular approuter + cap server with 2 different active consoles.
b. precompile ts on every restart (which cds-ts usually allows to avoid)

Additional context
inspired by this:
@nicoschoenteich
https://www.youtube.com/watch?v=bJIMIE7yjIE
https://github.com/SAP-samples/sap-tech-bytes/tree/cloud-foundry-basics/post6

[petermuessig]

@nicoschoenteich - maybe something to look into from your side?

[nicoschoenteich]

Hi @tiosteel,

We don't start the CAP server via the cds CLI, but programmatically, and unfortunately the serve module doesn't support TS. I guess the cds CLI handles that part before it gets to the actual serve. So I'm afraid, at this point we won't be able to handle CAP server written in TS.

Another option for you however could be to use the cds-plugin-ui5. This doesn't include the approuter magic, but you can start your CAP (TS) server and hook the UI5 app into this server. The project you shared doesn't seem to rely heavily on the approuter aspect, as it doesn't require real auth (at dev time), so this might be a good option.

Best, Nico