How can i have a interface check in typescript switch statements?

Question

I am using Typescript and redux

I want to compare passed action with an interface and then perform the task

export function counterReducer(
  state = initialState,
  action: CounterActionTypes
): CounterState {
  switch (action) {
    case IncrementAction:
      return { ...state, count: state.count + action.incBy };
    case action as DecerementAction:
      return { ...state, count: state.count + action.decBy };
    default:
      return state;
  }
}

Answer 1

Maybe you can check into type guards for that.

https://www.typescriptlang.org/docs/handbook/advanced-types.html

I would probably use redux-toolkit or redux-actions for that because it simplifies a lot your code and it has Typescript support