✨ handle resend errors (#62)

src/sender.ts

@@ -1,4 +1,5 @@
 import { Socket, createSocket } from 'dgram';
+import { EventEmitter } from 'events';
 import { multicastGroup } from './util';
 import { Packet, Options } from './packet';
 
@@ -47,9 +48,21 @@ export namespace Sender {
      */
     useUnicastDestination?: string;
   }
+
+  export interface EventMap {
+    changedResendStatus: boolean;
+    error: Error;
+  }
 }
 
-export class Sender {
+export declare interface Sender {
+  on<K extends keyof Sender.EventMap>(
+    type: K,
+    listener: (event: Sender.EventMap[K]) => void,
+  ): this;
+}
+
+export class Sender extends EventEmitter {
   private socket: Socket;
 
   private readonly port: Sender.Props['port'];
@@ -66,6 +79,8 @@ export class Sender {
 
   private sequence = 0;
 
+  public resendStatus = false;
+
   #loopId: NodeJS.Timeout | undefined;
 
   /**
@@ -84,6 +99,7 @@ export class Sender {
     iface,
     useUnicastDestination,
   }: Sender.Props) {
+    super();
     this.port = port;
     this.universe = universe;
     this.#destinationIp = useUnicastDestination || multicastGroup(universe);
@@ -123,7 +139,23 @@ export class Sender {
   }
 
   private reSend() {
-    if (this.#latestPacketOptions) this.send(this.#latestPacketOptions);
+    if (this.#latestPacketOptions) {
+      this.send(this.#latestPacketOptions)
+        .then(() => {
+          this.updateResendStatus(true);
+        })
+        .catch((err) => {
+          this.updateResendStatus(false);
+          this.emit('error', err);
+        });
+    }
+  }
+
+  private updateResendStatus(success: boolean) {
+    if (success !== this.resendStatus) {
+      this.resendStatus = success;
+      this.emit('changedResendStatus', success);
+    }
   }
 
   public close(): this {

test/integration.test.ts

@@ -48,6 +48,9 @@ describe('Receiver & Sender (integration test)', () => {
     try {
       const received: Packet[] = [];
       const errors: Error[] = [];
+      const receivedEvents: boolean[] = [];
+      Tx.on('changedResendStatus', (event) => receivedEvents.push(event));
+      Tx.on('error', (ex) => errors.push(ex));
       Rx.on('packet', (packet) => received.push(packet));
       collectErrors(Rx, errors);
 
@@ -58,6 +61,8 @@ describe('Receiver & Sender (integration test)', () => {
 
       assert.strictEqual(errors.length, 0);
       assert.strictEqual(received.length, 4); // send at 0s, 1s, 2s, 3s. Then at 3.5s we stop
+      assert.strictEqual(receivedEvents.length, 1);
+      assert.deepStrictEqual(receivedEvents[0], true);
       assert.deepStrictEqual(received[0]!.payload, { 1: 100 });
       assert.deepStrictEqual(received[1]!.payload, { 1: 100 });
       assert.deepStrictEqual(received[2]!.payload, { 1: 100 });