How to type reducer?

Question

typescript

const initialState = {
    board: [
        {
            id: 23,
            title: "I am board",

        }
    ]
}

How to type this construction???

Answer 1

type Board = {
    id: number;
    title: string;
}

type State = {
    board: Board[]
}

const initialState: State = {
    board: [
        {
            id: 23,
            title: "I am board",

        }
    ]
}

Answer 2

It would seem that only 2 words: typescript+ reducer.
And already at the very first link, off-line documentation on this topic pops up: https://redux.js.org/recipes/usage-with-typescript