Match commands case-insensitively

I cannot imagine any scenario in which anyone would want a bot to respond to /foo, /Foo and /FOO differently, so I suggest to match commands case-insensitively in Composer.command.

Usernames should be matched case-insensitively as well (#287).

Describe alternatives you’ve considered

1. hears(/^\/foo\b/i, handler) is less readable, and doesn’t check if usernames match (ie. /foo@notMyBot still runs) and if “command” isn’t just a code block starting with slash,
2. To achieve case-insensitivity and inspectability (router.handler) I wrote own command routing function, to be passed to Router constructor. BTW., check it out, I think you may be interested in bringing it into this repo.

[Colduction]

Hey mate, you can use this permutation snippet (I’m using it already!):

function letterCasePermutation(S) {
	S = S.toLowerCase();
	let len = S.length,
		ans = [];
	const dfs = (i, res = "") => {
		if (i < len) {
			dfs(i + 1, res + S[i]);
			if (S[i] >= "a") dfs(i + 1, res + S[i].toUpperCase());
		} else ans.push(res);
	};
	dfs(0);
	return ans;
}

[MKRhere]

should Composer.command check the username before trying the regex

Yes, that would be reasonable.