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Animated regular/calculated issue #504
Description
I am currently having an optional interpolation depending on an optional animated value
~transform=[|
Transform.translateY(
~translateY=
Animated.(
animatedFloat(
scrollYAnimatedValue
->Option.map(scrollYAnimatedValue =>
Animated.Value.add(
state.animation,
Value.interpolate(
scrollYAnimatedValue,
Interpolation.(
config(
~inputRange=[|(-200.), 1.|],
~outputRange=
fromFloatArray([|(-200.), 1.|]),
(),
)
),
),
)
)
->Option.getWithDefault(state.animation),
)
),
),
|],This code should work but doesn't compile, complaining that ->Option.getWithDefault(state.animation) isn't the same type as the interpolation.
Error: This expression has type
ReactNative.Animated.value(ReactNative.Animated.regular) =
ReactNative.Animated.value(ReactNative.Animated.regular)
but an expression was expected of type
ReactNative.Animated.value(ReactNative.Animated.calculated) =
ReactNative.Animated.value(ReactNative.Animated.calculated)
Type ReactNative.Animated.regular = ReactNative.Animated.regular
is not compatible with type
ReactNative.Animated.calculated = ReactNative.Animated.calculated
We should have something to tell that a regular & calculated are the same at the end, don't we?
Activity
wokalski commentedon May 17, 2019
ReactNative.Animated.value('a)is a polymorphicAnimated.valuetype. I suggest you change the order of the execution so that the output from different branches isTransform. You might also try playing with the type system in some other way.sgny commentedon May 18, 2019
I suppose we could use a method to convert a
value(calculated)tovalue(regular)but perhaps we don't really need to differentiate between those types in the first place. I had that opinion when reworking theAnimatedmodule, but as I don't know the motivation behind the differentiation in the first place, decided against raising the point as I might be missing the intention.@grabbou Since this came from your
Rebolteffort, perhaps you know the intention behind it? It appears first with reasonml-community/bs-react-native@ccb44f4.wokalski commentedon May 18, 2019
If you plug
regularin functions that expectcalculated(and vice versa) you’ll get runtime errors (unless something changed in more recent RN versions)sgny commentedon May 18, 2019
Do you have any concrete examples to try? Looking at function types, I'd expect chaining
Interpolation.interpolatewould be what causes runtime errors, such asHowever, perhaps
addormultiplycan still be `(value('a), value('a)) => value('a)'.wokalski commentedon May 18, 2019
@sgny you'd have to try. My memory might be failing me but I think those type definitions are correct.
sgny commentedon May 19, 2019
@wokalski I've been trying and it appears that the disctinction is still necessary. Chained interpolation is fine (at least so far as not causing runtime errors), but
setValueonvalue(calculated)is definitely not allowed, whether it is the result ofinterpolationoradd. I was under the mistaken impression that operations such asaddcreated a newAnimatedvalue, separate from the components (which I suppose would be mostly useless were that true), but as the result should track changes in its components, then operations such assetValueare meaningless.TLDR; current bindings represent a subtle understanding of provided functionality.
MoOx commentedon May 20, 2019
Ok, thanks for the explanation @wokalski @sgny. I will close this issue when this will be explained in the doc to avoid future similar question :)