lapis mulch
Let's say I have a union type as such, and want to implement a type guard, I can lie within the typeguard:
type A = {
on: false,
powered: false,
}
type B = {
on: true,
powered: true
}
type C = {
on: false,
powered: true
}
type AllStates = A | B | C
function isA(state: AllStates): state is A {
return state.on === false // but actually this could also be C
}
Is there a way to ensure that I can't accidentally do this?
If I wasn't using a type guard, my type could be narrowed appropriately:
const state = {} as unknown as AllStates
if (!state.on) {
// here state is inferred as A | C
}
Is this simply a situation where type guards aren't the tool I want?
steep carbon
can't
the entire point of typeguards is because typescript isn't powerful enough to figure this out itself
lapis mulch
yeah figured so
I mean I guess I could go through those if statements inside the typeguard to ensure for the branches I check, I'm not lying, but still isn't perfect