How to initialize array to tuple type in TypeScript?

I'm making sudoku web app with React/Redux. But I have encountered some problem with typings.

Current code:

// typedef
type Tuple9<T> = [T, T, T, T, T, T, T, T, T];

export type Board = Tuple9<Tuple9<number>>;

// code using board type, I want to fix getEmptyBoard() to more programmatic.
const getEmptyBoard: (() => Board) = () => {
  return [
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0, 0]
  ];
};

I want to fix getEmptyBoard() to more programmatic.

1. Is there good solution for this situation?
2. If 1, What is solution?

For 9 I would do what you have done.

Otherwise you would follow the old functional programming saying : If its pure on the outside, it doesn't matter if its impure on the inside and make a strategic use of Tuple9 type assertion:

type Tuple9<T> = [T, T, T, T, T, T, T, T, T];
function make9<T>(what: T): Tuple9<T> {
    return new Array(9).fill(what) as Tuple9<T>;
}

export type Board = Tuple9<Tuple9<number>>;
function makeBoard(): Board {
    return make9(make9(0));
}