Your app sounds like it used some advanced features, but I don’t think most apps are going to be computationally expensive in the way that local-AI, image processing, or crypto activities might be. I am not sure what qualifies as extremely large datasets, but I’d be surprised if keeping a few dozen objects in order is significantly lower in JS than Swift. Yes, it may be an order of magnitude slower - or ten orders - but that seems negligible if the total time for processing is still nanoseconds. Guess it always comes down to the task at hand.