fix(core): do not send pongs when cable is not connected

Fixes #33

packages/core/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## master
 
+- Do not try to send `pong` if cable is no longer connected. ([@palkan][])
+
 ## 0.7.12 (2024-01-08)
 
 - Omit `undefined` within Channels' params to fix invalid JSON serialization. ([@ardecvz][])

packages/core/action_cable_ext/index.js

@@ -152,6 +152,9 @@ export class ActionCableExtendedProtocol extends ActionCableProtocol {
   // Send pongs asynchrounously—no need to block the main thread
   async sendPong() {
     await new Promise(resolve => setTimeout(resolve, 0))
-    this.cable.send({ command: 'pong' })
+    // Only send pong if the connection is still open
+    if (this.cable.state === 'connected') {
+      this.cable.send({ command: 'pong' })
+    }
   }
 }

packages/core/action_cable_ext/index.test.ts

@@ -289,6 +289,7 @@ describe('receive', () => {
     })
 
     it('sends pong in response to ping', async () => {
+      cable.connected()
       protocol.receive({ type: 'ping', message: '42' })
       expect(cable.lastPingedAt).toEqual(42)
 
@@ -299,6 +300,15 @@ describe('receive', () => {
         command: 'pong'
       })
     })
+
+    it('does not try to send pong if cable is no longer connected', async () => {
+      protocol.receive({ type: 'ping', message: '42' })
+      expect(cable.lastPingedAt).toEqual(42)
+      cable.disconnected()
+      await new Promise(resolve => setTimeout(resolve, 0))
+
+      expect(cable.mailbox).toHaveLength(0)
+    })
   })
 })