fix: ignore sessionStore in the fetchSockets method

This field may contain circular references, which make `JSON.stringify`
throw.

Related: #421

lib/index.ts

@@ -298,12 +298,16 @@ export class RedisAdapter extends Adapter {
 
         response = JSON.stringify({
           requestId: request.requestId,
-          sockets: localSockets.map((socket) => ({
-            id: socket.id,
-            handshake: socket.handshake,
-            rooms: [...socket.rooms],
-            data: socket.data,
-          })),
+          sockets: localSockets.map((socket) => {
+            // remove sessionStore from handshake, as it may contain circular references
+            const { sessionStore, ...handshake } = socket.handshake;
+            return {
+              id: socket.id,
+              handshake,
+              rooms: [...socket.rooms],
+              data: socket.data,
+            };
+          }),
         });
 
         this.pubClient.publish(this.responseChannel, response);

test/index.ts

@@ -327,6 +327,7 @@ const shouldNotHappen = (done) => () => done(new Error("should not happen"));
       describe("fetchSockets", () => {
         it("returns all socket instances", async () => {
           socket2.data = "test";
+          socket2.handshake.sessionStore = "not included";
 
           const sockets = await namespace1.fetchSockets();
           expect(sockets).to.be.an(Array);
@@ -339,6 +340,7 @@ const shouldNotHappen = (done) => () => done(new Error("should not happen"));
             (socket) => socket.id === socket2.id
           );
           expect(remoteSocket2 === socket2).to.be(false);
+          delete socket2.handshake.sessionStore;
           expect(remoteSocket2.handshake).to.eql(socket2.handshake);
           expect(remoteSocket2.data).to.eql("test");
           expect(remoteSocket2.rooms.size).to.eql(1);