feat(socket.io): leave multiple rooms at once

packages/socket.io-adapter/lib/in-memory-adapter.ts

@@ -104,17 +104,30 @@ export class Adapter extends EventEmitter {
   }
 
   /**
-   * Removes a socket from a room.
+   * Removes a socket from one or multiple rooms.
    *
-   * @param {SocketId} id     the socket id
-   * @param {Room}     room   the room name
+   * @param {SocketId}      id     the socket id
+   * @param {Room|Set<Room>} rooms  the room name or a set of rooms
    */
-  public del(id: SocketId, room: Room): Promise<void> | void {
-    if (this.sids.has(id)) {
-      this.sids.get(id).delete(room);
+  public del(id: SocketId, rooms: Room | Set<Room>): Promise<void> | void {
+    const roomsToRemove = rooms instanceof Set ? rooms : new Set<Room>([rooms]);
+    const socketRooms = this.sids.get(id);
+
+    if (!socketRooms) {
+      for (const room of roomsToRemove) {
+        this._del(room, id);
+      }
+      return;
     }
 
-    this._del(room, id);
+    for (const room of roomsToRemove) {
+      socketRooms.delete(room);
+      this._del(room, id);
+    }
+
+    if (socketRooms.size === 0) {
+      this.sids.delete(id);
+    }
   }
 
   private _del(room: Room, id: SocketId) {

packages/socket.io-adapter/test/index.ts

@@ -26,6 +26,19 @@ describe("socket.io-adapter", () => {
     expect(adapter.sids.has("s2")).to.be(false);
   });
 
+  it("should remove multiple rooms with a single call", () => {
+    const adapter = new Adapter({ server: { encoder: null } });
+    adapter.addAll("s1", new Set(["r1", "r2", "r3"]));
+
+    adapter.del("s1", new Set(["r1", "r3"]));
+
+    expect(adapter.rooms.has("r1")).to.be(false);
+    expect(adapter.rooms.has("r3")).to.be(false);
+    expect(adapter.rooms.has("r2")).to.be(true);
+    expect(adapter.sids.get("s1").size).to.be(1);
+    expect(adapter.sids.get("s1").has("r2")).to.be(true);
+  });
+
   it("should return a list of sockets", async () => {
     const adapter = new Adapter({
       server: { encoder: null },

packages/socket.io/lib/socket.ts

@@ -476,16 +476,19 @@ export class Socket<
    *   socket.leave("room1");
    *
    *   // leave multiple rooms
-   *   socket.leave("room1").leave("room2");
+   *   socket.leave(["room1", "room2"]);
    * });
    *
-   * @param {String} room
+   * @param {String|Array} rooms - room or array of rooms
    * @return a Promise or nothing, depending on the adapter
    */
-  public leave(room: string): Promise<void> | void {
-    debug("leave room %s", room);
+  public leave(rooms: Room | Array<Room>): Promise<void> | void {
+    debug("leave room %s", rooms);
 
-    return this.adapter.del(this.id, room);
+    return this.adapter.del(
+      this.id,
+      new Set(Array.isArray(rooms) ? rooms : [rooms]),
+    );
   }
 
   /**

packages/socket.io/test/socket.ts

@@ -941,6 +941,23 @@ describe("socket", () => {
     });
   });
 
+  it("should leave multiple rooms at once", (done) => {
+    const io = new Server(0);
+    const client = createClient(io, "/");
+
+    io.on("connection", (socket) => {
+      Promise.resolve(socket.join(["room1", "room2"]))
+        .then(() => Promise.resolve(socket.leave(["room1", "room2"])))
+        .then(() => {
+          const adapter = io.of("/").adapter;
+          expect(adapter.rooms.has("room1")).to.be(false);
+          expect(adapter.rooms.has("room2")).to.be(false);
+          success(done, io, client);
+        })
+        .catch(done);
+    });
+  });
+
   describe("onAny", () => {
     it("should call listener", (done) => {
       const io = new Server(0);