StatelessWidget with Observer as a const?

[jshji252]

Hello team,

Thank you for amazing work, i hope i can contribute one day!

I was just thinking, when we have a Stateless widget (let's call it Page()) that uses a store and Observer widget, but does not use any arguments from the parent, Dart/Flutter allows us to instantiate that widget as a const, like const Page(). But Page() isn't technically const, is it? Or, is it const as its builder method's implementation doesn't change? I'd like to use const as much as possible to help performance. I don't understand all the technical details about const to find answers to this (but I am trying to!), so any help will be greatly appreciated!!

[amondnet]

Why does using const improve performance? Because the widget is not rebuilt on setState, i.e. the Page Widget itself is not rebuilt. Also, only the changed widgets inside the Page Widget are rebuilt by mobx, which improves performance.