I am a little confused about remember function . Compare to react usememory, what's the difference?

# compose-web

[sonder-joker]

I am a little confused about remember function . Compare to react usememory, what's the difference?

[Kirill Grouchnikov]

The very first Google result for "Compose vs React" gives this - https://tigeroakes.com/posts/react-to-compose-dictionary/#usememo--remember

[CLOVIS]

That page is not really helpful, because of how different state management works in Compose & React

[CLOVIS]

Remember is very similar to useMemo, but useState doesn't correspond to anything

[Arkady Bazhanov]

I thought useState is equivalent to remember { mutableStateOf(...) }

[CLOVIS]

I mean, yes and no. In its simpler form it is, but this works:

var a by mutableStateOf(false)

@Composable
fun Foo() {
  Text(a)
  Button(... { a = !a })
}

and this doesn't:

var a by useState(false)
// “hooks cannot be used outside of functional components”

val Foo = fc {
  //...
}

[CLOVIS]

Essentially Compose understands state modification when you call `State`'s setter, which can happen outside of a Composable (eg. global state) without any use of remember, but React only understands state modification when the useState setter is called, which can only happen locally in a component

[CLOVIS]

Basically, remember + mutableStateOf is much, much more powerful than useState

So if you learned React and you want to learn Compose, yes it is the equivalent, but if you come from Compose and try to learn React (like I did) it doesn't help you at all

[CLOVIS]

Also, remember etc don't have anything like the rules of hooks https://reactjs.org/docs/hooks-rules.html