Generice类型断言（TypeScript高级）

Question

Is there a way to choose generic T or K based on the value of error?

interface ReduxAction<T = undefined, K = undefined, M = undefined>{
type: string;
payload?: T | K;
meta: M
error?: boolean;
}

Answer 1

You can't, because the value of error is discovered in the execution phase, when typescript is already transpiled to javascript. In the fact that generics are a typescript feature and not present in the transpiled javascript output, it won't be possible to choose from one or the other while executing the javascript.

You can try to extends this interface and create two different interfaces, one for error and one for w/e your goal is.