Is there a way to modify the following code snippet to eliminate the need for as casting in order to pass the type check successfully?
type SupportedHandlerType = string | number | Date
type Handler<T> = (data: T[]) => void
function example<T extends SupportedHandlerType>(data: T[]) {
const handler = getHandler(data)
handler(data)
}
function stringHandler(data: string[]) {
}
function numberHandler(data: number[]) {
}
function dateHandler(data: Date[]) {
}
function getHandler<T>(data: T[]): Handler<T> {
const first = data[0]
if (typeof first == 'string') {
return stringHandler // Type 'T' is not assignable to type 'string'
}
if (typeof first == 'number') {
return numberHandler // another error here
}
return dateHandler // and here
}
The issue at hand involves a union of types in the SupportedHandlerType and using a generic function with one of these types. The function getHandler() should dynamically determine the type and return the corresponding handler, facing errors like
Type 'T' is not assignable to type 'string'Is there a way to refine the types to avoid these errors?