Print IRC error messages in red

lib/irc.js

@@ -7,6 +7,7 @@ export const RPL_TOPIC = "332";
 export const RPL_WHOREPLY = "352";
 export const RPL_NAMREPLY = "353";
 export const RPL_ENDOFNAMES = "366";
+export const ERR_NOMOTD = "422";
 export const ERR_PASSWDMISMATCH = "464";
 // https://ircv3.net/specs/extensions/sasl-3.1
 export const RPL_LOGGEDIN = "900";
@@ -240,3 +241,19 @@ export function isHighlight(text, nick) {
 		text = text.slice(i + nick.length);
 	}
 }
+
+export function isError(cmd) {
+	if (cmd >= "400" && cmd <= "568") {
+		return true;
+	}
+	switch (cmd) {
+	case ERR_NICKLOCKED:
+	case ERR_SASLFAIL:
+	case ERR_SASLTOOLONG:
+	case ERR_SASLABORTED:
+	case ERR_SASLALREADY:
+		return true;
+	default:
+		return false;
+	}
+}