Remove empty channels (#75)

feathersjs · Aug 21, 2018 · f986cba · f986cba
1 parent d27d177
commit f986cba
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Showing 3 changed files with 83 additions and 5 deletions.
diff --git a/packages/transport-commons/lib/channels/channel/base.js b/packages/transport-commons/lib/channels/channel/base.js
@@ -1,5 +1,9 @@
-class Channel {
+const { EventEmitter } = require('events');
+
+class Channel extends EventEmitter {
   constructor (connections = [], data = null) {
+    super();
+
     this.connections = connections;
     this.data = data;
   }
@@ -21,6 +25,10 @@ class Channel {
       }
     });
 
+    if (this.length === 0) {
+      this.emit('empty');
+    }
+
     return this;
   }
 

diff --git a/packages/transport-commons/lib/channels/mixins.js b/packages/transport-commons/lib/channels/mixins.js
@@ -24,14 +24,24 @@ exports.channelMixin = function channelMixin () {
       }
 
       if (names.length === 1) {
-        const name = names[0];
+        const [ name ] = names;
 
         if (Array.isArray(name)) {
           return this.channel(...name);
         }
 
-        return this[CHANNELS][name] ||
-          (this[CHANNELS][name] = new Channel());
+        if (!this[CHANNELS][name]) {
+          const channel = new Channel();
+
+          channel.once('empty', () => {
+            channel.removeAllListeners();
+            delete this[CHANNELS][name];
+          });
+
+          this[CHANNELS][name] = channel;
+        }
+
+        return this[CHANNELS][name];
       }
 
       const channels = names.map(name => this.channel(name));

diff --git a/packages/transport-commons/test/channels/channel.test.js b/packages/transport-commons/test/channels/channel.test.js
@@ -4,14 +4,16 @@ const channels = require('../../lib/channels');
 const Channel = require('../../lib/channels/channel/base');
 const CombinedChannel = require('../../lib/channels/channel/combined');
 
+const { CHANNELS } = channels.keys;
+
 describe('app.channel', () => {
   let app;
 
   beforeEach(() => {
     app = feathers().configure(channels());
   });
 
-  describe('leaf channels', () => {
+  describe('base channels', () => {
     it('creates a new channel, app.channels has names', () => {
       assert.ok(app.channel('test') instanceof Channel);
       assert.deepEqual(app.channels, ['test']);
@@ -97,6 +99,64 @@ describe('app.channel', () => {
       assert.ok(test !== withData);
       assert.deepEqual(withData.data, data);
     });
+
+    describe('empty channels', () => {
+      it('is an EventEmitter', () => {
+        const channel = app.channel('emitchannel');
+
+        return new Promise((resolve) => {
+          channel.once('message', data => {
+            assert.equal(data, 'hello');
+            resolve();
+          });
+
+          channel.emit('message', 'hello');
+        });
+      });
+
+      it('empty', done => {
+        const channel = app.channel('test');
+        const c1 = { id: 1 };
+        const c2 = { id: 2 };
+
+        channel.once('empty', done);
+
+        channel.join(c1, c2);
+        channel.leave(c1);
+        channel.leave(c2);
+      });
+
+      it('removes an empty channel', () => {
+        const channel = app.channel('test');
+        const appChannels = app[CHANNELS];
+        const c1 = { id: 1 };
+
+        channel.join(c1);
+
+        assert.ok(appChannels.test);
+        assert.equal(Object.keys(appChannels).length, 1);
+        channel.leave(c1);
+
+        assert.ok(app[CHANNELS].test === undefined);
+        assert.equal(Object.keys(appChannels).length, 0);
+      });
+
+      it('removes all event listeners from an empty channel', () => {
+        const channel = app.channel('testing');
+        const connection = { id: 1 };
+
+        channel.on('something', () => {});
+        assert.equal(channel.listenerCount('something'), 1);
+        assert.equal(channel.listenerCount('empty'), 1);
+
+        channel.join(connection).leave(connection);
+
+        assert.ok(app[CHANNELS].testing === undefined);
+
+        assert.equal(channel.listenerCount('something'), 0);
+        assert.equal(channel.listenerCount('empty'), 0);
+      });
+    });
   });
 
   describe('combined channels', () => {