[jbritton]

I have built a Qt app using this approach. I created a vdom for Qt to allow for the view to be a pure function of state. However, the app also has some extensive animation, and it runs on a slow embedded processor. I needed an escape hatch to not recompute the entire view on every animation frame on some screens. I think using something like MobX computed expressions could provide the necessary performance to avoid needing the escape hatch. However, the code base is now large and dynamically typed and extensive change is now hard. In general this approach involves recomputing the entire UI and diffing against the previous UI on every state change or maybe every 33ms. If the above takes too long, then it’s a problem.

[brundolf]

In cases where you're working with primitives/immutable values (constant-time comparable for change detection), you can use plain-old memoization to avoid redundant work. If you're familiar with React, this is basically what PureComponent tries to do. The limitation, of course, is that this doesn't work with arbitrarily-deep, arbitrarily-mutable state objects. That's where really MobX shines.