Thanks for thinking about it.
This is what I have implemented in the past, although with
findOne in a helper rather than in
transform. However, it seems having a reactive cursor returning hundreds of texteareas, each one having its own individual reactive cursors, lead to poor performance. I didn’t measure it precisely, though.
I tried another solution: mirroring my collection in a local collection using
observeChange. This allows avoiding the copy of the non-reactive fields over to the local collection, hence preventing reactivity. It seemed better in terms of performance, but the mirroring logic is delicate and error-prone (avoiding to copy a field over is easy, but the problem is to decide when you finally want to copy it over so that your local collection is up to date).
So right now I entirely removed the feature.