core(mux-relay): fix TypeError: Cannot read property 'push' of null

src/core/mux-relay.js

@@ -241,13 +241,13 @@ export class MuxRelay extends EventEmitter {
 
     // once connect, flush all pending frames
     const frames = this._pendingFrames.get(cid);
-    if (frames) {
+    if (frames && !outbound.destroyed) {
       const buffer = Buffer.concat(frames);
-      this._pendingFrames.delete(cid);
       outbound.write(buffer);
       outbound.__tracker.trace(PIPE_DECODE, buffer.length);
       setImmediate(() => this.emit('_read', buffer.length));
     }
+    this._pendingFrames.delete(cid);
   };
 
   onDataFrame = ({ cid, data }) => {

src/transports/defs.js

@@ -12,6 +12,8 @@ class Bound extends EventEmitter {
 
   _conn = null;
 
+  _destroyed = false;
+
   constructor({ config, source, conn }) {
     super();
     this._config = config;
@@ -39,6 +41,10 @@ class Bound extends EventEmitter {
     return true;
   }
 
+  get destroyed() {
+    return this._destroyed;
+  }
+
   onBroadcast() {
 
   }

src/transports/h2.js

@@ -6,8 +6,6 @@ export class Http2Inbound extends Inbound {
 
   _stream = null;
 
-  _destroyed = false;
-
   constructor(props) {
     super(props);
     this._stream = this._conn;
@@ -81,8 +79,6 @@ export class Http2Outbound extends Outbound {
 
   _stream = null;
 
-  _destroyed = false;
-
   get name() {
     return 'h2:outbound';
   }

src/transports/tcp.js

@@ -14,8 +14,6 @@ export class TcpInbound extends Inbound {
 
   _socket = null;
 
-  _destroyed = false;
-
   constructor(props) {
     super(props);
     this._socket = this._conn;
@@ -147,8 +145,6 @@ export class TcpOutbound extends Outbound {
 
   _socket = null;
 
-  _destroyed = false;
-
   get name() {
     return 'tcp:outbound';
   }

src/transports/ws.js

@@ -13,8 +13,6 @@ export class WsInbound extends Inbound {
 
   _socket = null;
 
-  _destroyed = false;
-
   constructor(props) {
     super(props);
     this._socket = this._conn;
@@ -81,8 +79,6 @@ export class WsOutbound extends Outbound {
 
   _socket = null;
 
-  _destroyed = false;
-
   get name() {
     return 'ws:outbound';
   }