Typescript Determining type of generic.

Hi, I have the following generic function

const handleContinue = <T extends A | B>(data: T) => {}

const handleContinue = <T extends A | B>(data: T) => {}

How can I check inside this function when data = A, or when data = B?

3 Replies

Xaohs•2y ago

I'd like to do something along the lines of

if (data === typeof A) { ..... } 
if (data === typeof B) { ..... }

if (data === typeof A) { ..... } 
if (data === typeof B) { ..... }

Unknown User•2y ago

Message Not Public

Xaohs•2y ago

Hmm not the cleneast solution but it works I guess. I did it as follows

function isA(data: A | B): data is A{
  return (data as A).property !== undefined;
}

function isA(data: A | B): data is A{
  return (data as A).property !== undefined;
}

And i just type check it by isA(data)