lib/irc: add formatURL

lib/irc.js

@@ -839,6 +839,17 @@ export function parseURL(str) {
 	return { host, enttype, entity };
 }
 
+export function formatURL({ host, enttype, entity } = {}) {
+	host = host || "";
+	entity = entity || "";
+
+	let s = "irc://" + host + "/" + encodeURIComponent(entity);
+	if (enttype) {
+		s += ",is" + enttype;
+	}
+	return s;
+}
+
 export class CapRegistry {
 	available = new Map();
 	enabled = new Set();