Calls the given callback() function when the Konami Code is entered. The 'keyPhrase' array can be modified to whatever you like!

ko.js

function konami(callback) {
	const keyPhrase = [
		"ArrowUp", "ArrowUp", "ArrowDown", "ArrowDown", "ArrowLeft", "ArrowRight", "ArrowLeft", "ArrowRight", "b", "a", "Enter"
	];
	let index = 0;
	$(document).on("keydown", (k) => { // get the key that was pressed
		k.key === keyPhrase[index] ? index++ : (index = 0); // goto next index for each correct key press
		if (index === keyPhrase.length) { // if the entire keyPhrase is entered correctly...
			index = 0; // clear the index so we can use this function again
			callback(); // call the passed-in function
		}
	});
}