feat: support unsubscribe all for pubsub (#321)

* chore: unsubscribe without handler reference

* chore: added unsubscribe 1 param

src/pubsub.js

@@ -37,8 +37,11 @@ module.exports = (node) => {
       if (!node.isStarted() && !floodSub.started) {
         throw new Error(NOT_STARTED_YET)
       }
-
+      if (!handler && !callback) {
-      floodSub.removeListener(topic, handler)
+        floodSub.removeAllListeners(topic)
+      } else {
+        floodSub.removeListener(topic, handler)
+      }
 
       if (floodSub.listenerCount(topic) === 0) {
         floodSub.unsubscribe(topic)

test/pubsub.node.js

@@ -87,6 +87,51 @@ describe('.pubsub', () => {
         expect(err).to.not.exist().mark()
       })
     })
+    it('start two nodes and send one message, then unsubscribe without handler', (done) => {
+      // Check the final series error, and the publish handler
+      expect(3).checks(done)
+
+      let nodes
+      const data = Buffer.from('test')
+      const handler = (msg) => {
+        // verify the data is correct and mark the expect
+        expect(msg.data).to.eql(data).mark()
+      }
+
+      series([
+        // Start the nodes
+        (cb) => startTwo((err, _nodes) => {
+          nodes = _nodes
+          cb(err)
+        }),
+        // subscribe on the first
+        (cb) => nodes[0].pubsub.subscribe('pubsub', handler, cb),
+        // Wait a moment before publishing
+        (cb) => setTimeout(cb, 500),
+        // publish on the second
+        (cb) => nodes[1].pubsub.publish('pubsub', data, cb),
+        // Wait a moment before unsubscribing
+        (cb) => setTimeout(cb, 500),
+        // unsubscribe on the first
+        (cb) => {
+          nodes[0].pubsub.unsubscribe('pubsub')
+          // Wait a moment to make sure the ubsubscribe-from-all worked
+          setTimeout(cb, 500)
+        },
+        // Verify unsubscribed
+        (cb) => {
+          nodes[0].pubsub.ls((err, topics) => {
+            expect(topics.length).to.eql(0).mark()
+            cb(err)
+          })
+        },
+        // Stop both nodes
+        (cb) => stopTwo(nodes, cb)
+      ], (err) => {
+        // Verify there was no error, and mark the expect
+        expect(err).to.not.exist().mark()
+      })
+    })
   })
 
   describe('.pubsub off', () => {