Better to support (#161)

* Socket can send message to room

* Added possibility to message multiple rooms via chaining

* Fixed lint errors

src/helpers/dedupe.js

@@ -0,0 +1,4 @@
+export default arr => arr.reduce((deduped, b) => {
+  if (deduped.indexOf(b) > -1) return deduped;
+  return deduped.concat(b);
+}, []);

src/server.js

@@ -4,6 +4,7 @@ import networkBridge from './network-bridge';
 import CLOSE_CODES from './helpers/close-codes';
 import normalize from './helpers/normalize-url';
 import globalObject from './helpers/global-object';
+import dedupe from './helpers/dedupe';
 import { createEvent, createMessageEvent, createCloseEvent } from './event-factory';
 
 /*
@@ -164,10 +165,15 @@ class Server extends EventTarget {
   *
   * e.g. server.to('my-room').emit('hi!');
   */
-  to(room, broadcaster) {
+  to(room, broadcaster, broadcastList = []) {
     const self = this;
-    const websockets = networkBridge.websocketsLookup(this.url, room, broadcaster);
+    const websockets = dedupe(broadcastList.concat(
+      networkBridge.websocketsLookup(this.url, room, broadcaster)
+    ));
+
     return {
+      to: (chainedRoom, chainedBroadcaster) =>
+        this.to.call(this, chainedRoom, chainedBroadcaster, websockets),
       emit(event, data) {
         self.emit(event, data, { websockets });
       }

src/socket-io.js

@@ -187,6 +187,14 @@ class SocketIO extends EventTarget {
     networkBridge.removeMembershipFromRoom(this, room);
   }
 
+  to(room) {
+    return this.broadcast.to(room);
+  }
+
+  in() {
+    return this.to.apply(null, arguments);
+  }
+
   /*
    * Invokes all listener functions that are listening to the given event.type property. Each
    * listener will be passed the event as the first argument.

tests/functional/socket-io.test.js

@@ -139,6 +139,26 @@ test.cb('a socket can join and leave a room', (t) => {
   });
 });
 
+test.cb('a socket can emit to a room', (t) => {
+  const server = new Server('ws://roomy');
+  const socketFoo = io('ws://roomy');
+  const socketBar = io('ws://roomy');
+
+  socketFoo.on('connect', () => {
+    socketFoo.join('room');
+  });
+  socketFoo.on('room-talk', () => {
+    t.true(true);
+    server.close();
+    t.end();
+  });
+
+  socketBar.on('connect', () => {
+    socketBar.join('room');
+    socketBar.to('room').emit('room-talk');
+  });
+});
+
 test.cb('Client can emit with multiple arguments', (t) => {
   const server = new Server('foobar');
   server.on('client-event', (...data) => {
@@ -171,3 +191,40 @@ test.cb('Server can emit with multiple arguments', (t) => {
     t.end();
   });
 });
+
+test.cb('Server can emit to multiple rooms', (t) => {
+  const server = new Server('ws://chat');
+  const socket1 = io('ws://chat');
+  const socket2 = io('ws://chat');
+
+  let connectedCount = 0;
+  const checkConnected = () => {
+    connectedCount += 1;
+    if (connectedCount === 2) {
+      server.to('room1').to('room2').emit('good-response');
+    }
+  };
+
+  let goodResponses = 0;
+  const checkGoodResponses = (socketId) => {
+    goodResponses += 1;
+    if (goodResponses === 2) {
+      t.true(true);
+      server.close();
+      t.end();
+    }
+  };
+
+  socket1.on('good-response', checkGoodResponses.bind(null, 1));
+  socket2.on('good-response', checkGoodResponses.bind(null, 2));
+
+  socket1.on('connect', () => {
+    socket1.join('room1');
+    checkConnected();
+  });
+
+  socket2.on('connect', () => {
+    socket2.join('room2');
+    checkConnected();
+  });
+});