fix error in case same subscription is unsubscribed multiple times

Author: hpihkala

streamr-client.js

@@ -356,7 +356,7 @@ StreamrClient.prototype.unsubscribe = function(sub) {
 		throw "unsubscribe: please give a Subscription object as an argument!"
 
 	// If this is the last subscription for this stream, unsubscribe the client too
-	if (this.subsByStream[sub.streamId].length === 1 && this.connected && !this.disconnecting && sub.isSubscribed() && !sub.unsubscribing) {
+	if (this.subsByStream[sub.streamId] !== undefined && this.subsByStream[sub.streamId].length === 1 && this.connected && !this.disconnecting && sub.isSubscribed() && !sub.unsubscribing) {
 		sub.unsubscribing = true
 		this._requestUnsubscribe(sub.streamId)
 	}

test/test.streamr-client.js

@@ -714,6 +714,25 @@ describe('StreamrClient', function() {
 			})
 		})
 
+		it('should not send another unsubscribed event if the same Subscription is unsubscribed multiple times', function(done) {
+			var sub = client.subscribe("stream1", function(message) {})
+			client.connect()
+
+			client.socket.once('subscribed', function() {
+				client.unsubscribe(sub)
+			})
+
+			client.socket.once('unsubscribed', function() {
+				setTimeout(function() {
+					client.unsubscribe(sub)
+					done()
+					client.socket.once('unsubscribed', function() {
+						throw "Unsubscribed event sent more than once for same Subscription!"
+					})
+				})
+			})
+		})
+
 		it('should not unsubscribe the client from a stream when there are subscriptions remaining for that stream', function(done) {
 			var sub1 = client.subscribe("stream1", function(message) {})
 			var sub2 = client.subscribe("stream1", function(message) {})