Hi. I have a question about how to choose

ambientOf

and

staticAmbientOf

. Since

staticAmbientOf

will force all children doing recomposition, seems like

ambientOf

is more efficient. But after search the source code, I found that there are more occurrences of

staticAmbientOf

. I understand that most of them are rarely changed and the comment of

staticAmbientOf

says:

A static ambient should be only be used when the value provided is highly unlikely to change.

But why not just using

staticOf

? Are there any circumstances that we must do all children recomposition? I would be very happy if there were some guides to told me how to choose between

ambientOf

and

staticAmbientOf

. Thanks!

If

ambientOf

were purely more efficient, we wouldn't even provide

staticAmbientOf

. But it's not true, the costs are just different. As you mentioned,

staticAmbientOf

will force a recomposition of all children, which means you pay the cost (and may drop frame) when you change the ambient, but it is cheaper to setup because you aren't setting up large numbers of subscriptions on every usage of the ambient.

ambientOf

in contrast does more targeted updates, which can make recomposition faster, but you pay the cost when building/maintaining the initial tree, making your whole app slower even in cases where the ambient never changes. Both have pros and cons, but static ambients are probably more common because most things which are ambient values should be consumed by large numbers of nodes (otherwise, you should be passing them as parameters) and things that are consumed by large numbers of nodes empirically seem to change not very often (eg. user's preferred language).

Thanks for your response!

but you pay the cost when building/maintaining the initial tree

I haven’t thought of the cost of using

State

(wrapped by the

ambientOf

) and didn’t notice that resolving a lot of dependencies for a

State

can take much time. So the principle of choosing

staticAmbientOf

and

ambientOf

basically depends on whether we need to do more reading or writing, right?

yes