Here is the code snippet I'm working with:
interface ItemA{
x:number
y:string
}
interface ItemB{
z:boolean
}
interface Data{
a:ItemA[]
b:ItemB[]
bool:boolean
}
type ItemType=keyof Data&('a'|'b')
function f<K extends ItemType>(data:Data,key:K):void{
type T=Data[K] extends (infer TT)[]?TT:never
const values:T[]=data[key]
values.forEach(
(t:T):void=>{
console.log(t)
}
)
}
I want to assign T variable to be of type ItemA when the key parameter is equal to 'a', and of type ItemB when it's 'b'. This way, the values array could either be of type ItemA[] or ItemB[]. How can I make this work?
When trying to implement this functionality, I encountered the following TypeScript error:
20:9 Type 'ItemA[] | ItemB[]' is not assignable to type 'T[]'.
Type 'ItemA[]' is not assignable to type 'T[]'.
Type 'ItemA' is not assignable to type 'T'.