release: WRNexusJS 0.8.0

packages/pubsub/src/index.ts

@@ -15,11 +15,14 @@ export type Handler<T = unknown> = (message: T, topic: string) => void | Promise
 export interface PubSubDriver {
   publish(topic: string, message: unknown): void | Promise<void>;
   subscribe(pattern: string, handler: Handler): () => void;
+  close?(): void | Promise<void>;
 }
 
 export interface PubSub {
   publish<T = unknown>(topic: string, message: T): Promise<void>;
   subscribe<T = unknown>(pattern: string, handler: Handler<T>): () => void;
+  /** Stop new work, remove subscriptions, and close the backing driver. */
+  close(): Promise<void>;
 }
 
 function patternMatches(pattern: string, topic: string): boolean {
@@ -31,14 +34,19 @@ function patternMatches(pattern: string, topic: string): boolean {
 /** In-process pub/sub driver (default). */
 export function memoryDriver(): PubSubDriver {
   const subs = new Map<string, Set<Handler>>();
+  let closed = false;
   return {
-    publish(topic, message) {
+    async publish(topic, message) {
+      if (closed) throw new Error("WRN-PUBSUB-CLOSED: pubsub driver is closed");
+      const pending: Promise<void>[] = [];
       for (const [pattern, handlers] of subs) {
         if (!patternMatches(pattern, topic)) continue;
-        for (const handler of handlers) void handler(message, topic);
+        for (const handler of handlers) pending.push(Promise.resolve(handler(message, topic)));
       }
+      await Promise.all(pending);
     },
     subscribe(pattern, handler) {
+      if (closed) throw new Error("WRN-PUBSUB-CLOSED: pubsub driver is closed");
       let set = subs.get(pattern);
       if (!set) subs.set(pattern, (set = new Set()));
       set.add(handler);
@@ -47,19 +55,35 @@ export function memoryDriver(): PubSubDriver {
         if (!set!.size) subs.delete(pattern);
       };
     },
+    close() {
+      closed = true;
+      subs.clear();
+    },
   };
 }
 
 /** Create a pub/sub bus over a driver (in-memory by default). */
 export function createPubSub(driver: PubSubDriver = memoryDriver()): PubSub {
+  let closed = false;
   return {
     async publish(topic, message) {
+      if (closed) throw new Error("WRN-PUBSUB-CLOSED: pubsub is closed");
+      if (!topic.trim()) throw new TypeError("pubsub topic cannot be empty");
       await driver.publish(topic, message);
     },
     subscribe(pattern, handler) {
+      if (closed) throw new Error("WRN-PUBSUB-CLOSED: pubsub is closed");
+      if (!pattern.trim()) throw new TypeError("pubsub pattern cannot be empty");
       return driver.subscribe(pattern, handler as Handler);
     },
+    async close() {
+      if (closed) return;
+      closed = true;
+      await driver.close?.();
+    },
   };
 }
 export { createResilientPubSub, PresenceChannel } from "./resilient.ts";
 export type { MessageEnvelope, ResilientPubSubOptions, PresenceMember } from "./resilient.ts";
+export { natsDriver, kafkaDriver } from "./brokers.ts";
+export type { NatsClient, KafkaClient } from "./brokers.ts";