usePrevious
function usePrevious<T>(
scope: Fusion.Scope,
state: Fusion.UsedAs<T>,
predicate: ((T, T) -> boolean)?
): Fusion.StateObject<T>
Returns a state object with the previous value of an observable state object. Initially outputs nil.
Parameters
scope : Fusion.Scope
The scope to store cleanup tasks.
state : Fusion.UsedAs<T>
The state object to observe for changes.
predicate : ((T, T) -> boolean)?
The predicate function to assert if the value is newer. Defaults to Fusion's similarity rules.
Returns -> Fusion.StateObject<T>
A state object with the previous value of the state object. Initially outputs nil.
Example Usage
local function randomColor(): Color3
return Color3.fromHSV(math.random(0, 360), 0.75, 1)
end
local currentColor = scope:Value(randomColor())
local previousColor = scope:usePrevious(currentColor)
scope:useInterval(1, function()
currentColor:set(randomColor)
end)
scope:Observer(currentColor):onChange(function()
print("Current color:", peek(currentColor), "Previous color:", peek(previousColor))
end)