feat: add subscribeToUpdates method to listen for updates

src/index.ts

@@ -1,13 +1,19 @@
 import { ActiveQuery, addHandler } from "@lumeweb/libkernel/module";
+import { EventEmitter } from "events";
 
 const types: Set<string> = new Set<string>();
 const networks: Map<string, Set<string>> = new Map<string, Set<string>>();
 
+const events = new EventEmitter();
+
 addHandler("registerType", handleRegisterType);
 addHandler("getTypes", handleGetTypes);
 addHandler("getNetworkTypes", handleGetNetworkTypes);
 addHandler("getNetworksByType", handleGetNetworksByType);
 addHandler("registerNetwork", handleRegisterNetwork);
+addHandler("subscribeToUpdates", handleSubscribeToUpdates, {
+  receiveUpdates: true,
+});
 
 function handleRegisterType(aq: ActiveQuery) {
   types.add(aq.callerInput);
@@ -38,6 +44,8 @@ function handleRegisterNetwork(aq: ActiveQuery) {
     networks.set(aq.domain, new Set([...aq.callerInput.types]));
   }
 
+  events.emit("update");
+
   aq.respond();
 }
 
@@ -76,3 +84,16 @@ function handleGetNetworksByType(aq: ActiveQuery) {
       .map((item) => item[0]),
   );
 }
+
+function handleSubscribeToUpdates(aq: ActiveQuery) {
+  const cb = () => {
+    aq.sendUpdate();
+  };
+
+  events.on("update", cb);
+
+  aq.setReceiveUpdate?.(() => {
+    events.off("update", cb);
+    aq.respond();
+  });
+}