> if you don't mess with useMemo (which you generally shouldn't)
why? is this not the primary way to re-init expensive internal component state when specific props change?
why? is this not the primary way to re-init expensive internal component state when specific props change?
In general, I think it's always a mistake to tell people "don't use this tool because you may shoot yourself in the foot", best to explain the when and why. But I do have a problem when the tool has just stupid defaults that make it harder to use correctly in the first place.
> I think as developers, we tend to overestimate how expensive re-renders are. In the case of our Decoration component, re-renders are lightning quick.
Certainly it's there for a reason, and you may have expensive operations, but in my experience developers reach for useMemo much too early and often, and it just adds complexity to their functions. The cost of checking the parameters for changes adds overhead that may be more expensive than just re-doing the "expensive" operation. My rule of thumb is if the operation is less than O(n) where n < ~5000 I don't reach for useMemo.
There have been some benchmarks done on this, and when it pays off to use.