Simple konami code hook

use-konami.ts

import { useEffect, useRef } from "react";

const UP = "ArrowUp";
const DOWN = "ArrowDown";
const LEFT = "ArrowLeft";
const RIGHT = "ArrowRight";
const B = "b";
const A = "a";

export const KONAMI_CODE = [UP, UP, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT, B, A];

const isBrowser = typeof window !== "undefined";

export const useKonami = (callback?) => {
  const index = useRef(0);

  useEffect(() => {
    const handleKeyDown = (event) => {
      let currKey = KONAMI_CODE[index.current];

      if (event.key == currKey) {
        index.current++;
      } else {
        index.current = 0;
      }

      if (index.current === KONAMI_CODE.length) {
        index.current = 0;
        console.log("k o n a m i");
        if (callback) callback();
      }
    };

    if (isBrowser) window.addEventListener("keydown", handleKeyDown);

    return () => {
      if (isBrowser) window.removeEventListener("keydown", handleKeyDown);
    };
  }, []);
};