Yocto recipes to install & setup Node-RED

I inherited a project where Node-RED was running on a Raspeberry Pi board. People before me created all the flows. Those flows need more node types than installed by default. My job is to migrate this project to another platform built with Yocto. I have managed to create a recipe to install Node-RED as a service, but I am struggling with configuration. I would like my recipe to install the missing nodes in the image (using npm), and to load flows.json automatically. For this second wish, I installed settings.js pointing to the flows.json file, but it does not work.
Are there any simple recipes existing somewhere that do that ?
I think this kind configuration must not be unusual.
Thank your for any help/tips.