Listening for pressing keys from string in correct order and giving callback

onword.js

onword = {
reg: {},
debug: false,
set: (a, c, s) => {
	
	if (!s) a = a.toLowerCase();

document.addEventListener("keypress", (b) => {
	onword.listen(a, b, c, s);
});

onword.reg[a] = 0;

},

listen: (a, b, c, s) => {

	if (!s) var key = b.key.toLowerCase(); else var key = b.key;
	
	if (a[onword.reg[a]] && key === a[onword.reg[a]]) {
		onword.reg[a]++;
		if (onword.debug) console.log(key+" === "+a[onword.reg[a]-1]);
	} else {
		var m = onword.reg[a];
		onword.reg[a] = 0;
		if (onword.debug) console.log(key+" !== "+a[m]);
	}
	if (onword.reg[a] >= a.length) {c(); onword.reg[a] = 0;}

}
}

// onword.set(): Add new KeyPress-listener
// @param a* {string} - String we're listening for
// @param c* {function} - Callback
// @param s {bool} - Case-sensitive
onword.set("Hello World", ()=>{alert("Welcome to JavaScript!");})