this.children is undefined for ParentBroadcastAdapter broadcast

[charliegracie]

I am getting an error in my application after moving up to version 4.7.5. When I run with previous versions, including 4.7.4, everything works properly. The error I receive is:

node_modules/socket.io/dist/parent-namespace.js:88
        this.children.forEach((nsp) => {
                      ^

TypeError: Cannot read properties of undefined (reading 'forEach')
    at ParentBroadcastAdapter.broadcast (node_modules/socket.io/dist/parent-namespace.js:88:23)
    at BroadcastOperator.emit (node_modules/socket.io/dist/broadcast-operator.js:169:26)
    at Socket.<anonymous> (server.js:60:33)
    at Socket.emit (node:events:520:28)
    at Socket.emitReserved (node_modules/socket.io/dist/typed-events.js:56:22)
    at Socket._onclose (node_modules/socket.io/dist/socket.js:547:14)
    at Client.onclose (node_modules/socket.io/dist/client.js:247:20)
    at Socket.emit (node:events:532:35)
    at Socket.onClose (node_modules/engine.io/build/socket.js:304:18)
    at Object.onceWrapper (node:events:639:28)

When the following code was added in PR 4950 it appears that the code forgot to store or copy the children parameter.

socket.io/lib/parent-namespace.ts

Line 121 in b0568b2

this.children.forEach((nsp) => {

I think the code should be modified something like:

class ParentBroadcastAdapter extends Adapter {
  private readonly children: Set<
    Namespace<ListenEvents, EmitEvents, ServerSideEvents, SocketData>
  > ;
  constructor(parentNsp: any, private readonly children: Set<Namespace>) {
    super(parentNsp);

     this.children = children;
  }

  broadcast(packet: any, opts: BroadcastOptions) {
    this.children.forEach((nsp) => {
      nsp.adapter.broadcast(packet, opts);
    });
  }
}

[darrachequesne]

Hi! That's weird, the children attribute should be initialized with the readonly tag:

socket.io/lib/parent-namespace.ts

Lines 116 to 118 in b0568b2

	constructor(parentNsp: any, private readonly children: Set<Namespace>) {
	super(parentNsp);
	}

In dist/parent-namespace.js:

class ParentBroadcastAdapter extends socket_io_adapter_1.Adapter {
    constructor(parentNsp, children) {
        super(parentNsp);
        this.children = children;
    }
    broadcast(packet, opts) {
        this.children.forEach((nsp) => {
            nsp.adapter.broadcast(packet, opts);
        });
    }
}

So I'm not sure how this.children can be undefined there... Thoughts?

[peterjuras]

Hi,
I'm experiencing the same issue. I'm using https://github.com/socketio/socket.io-redis-streams-adapter maybe that is the source of the issue?

[gkt5015]

Hi, is there an update on this?

I believe the issue here is that this.children isn't declared yet when super is called in the ParentNamespace class. The constructor of Namespace will call _initAdapter of the subclass with the undefined value. Prior to the change, this.children was enclosed in the function so it wasn't an issue.

Perhaps one way to change this would be:

class ParentBroadcastAdapter extends socket_io_adapter_1.Adapter {
    constructor(parentNsp) {
        super(parentNsp);
        this.parentNsp = parentNsp;
    }
    broadcast(packet, opts) {
        this.parentNsp.children.forEach((nsp) => {
            nsp.adapter.broadcast(packet, opts);
        });
    }
}

[Hippopop]

Hi! I am using the latest version of the package. And I am facing this exact same issue!
I'm not sure why that's happening and how to resolve it?!?

/Volumes/Development/NodeJs/Personal/full-stack-chat-app/chat-server/node_modules/socket.io/dist/parent-namespace.js:88
        this.children.forEach((nsp) => {
                      ^
TypeError: Cannot read properties of undefined (reading 'forEach')
    at ParentBroadcastAdapter.broadcast (/Volumes/Development/NodeJs/Personal/full-stack-chat-app/chat-server/node_modules/socket.io/dist/parent-namespace.js:88:23)
    at BroadcastOperator.emit (/Volumes/Development/NodeJs/Personal/full-stack-chat-app/chat-server/node_modules/socket.io/dist/broadcast-operator.js:169:26)
    at Namespace.<anonymous> (/Volumes/Development/NodeJs/Personal/full-stack-chat-app/chat-server/src/socket_io/chat_process/chat_process.ts:35:14)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)

[darrachequesne]

@Hippopop I don't think the fix has been released yet. Let me check.

[Hippopop]

@darrachequesne Yeah, I think that's the case. But I've been trying to to use the package/library directly from the GitHub. And use the #main brunch. Sadly that's not working either.

npm error Cannot read properties of undefined (reading 'spec')
npm error A complete log of this run can be found in: ...

Is there anything I can do here?!? I'm a bit new with Node.Js and npm.