Better device present/absent handling by separating it from the status event.

res/app/scripts/services/deviceService.js

@@ -1,13 +1,56 @@
 define(['./module', 'oboe'], function(mod, oboe) {
-  function DevicesServiceFactory($rootScope, socketService) {
+  function DevicesServiceFactory($rootScope, socket) {
     var deviceService = {
       devices: []
+    , devicesBySerial: {}
     }
 
+    function get(data) {
+      return deviceService.devices[deviceService.devicesBySerial[data.serial]]
+    }
+
+    function insert(data, alter) {
+      deviceService.devicesBySerial[data.serial] =
+        deviceService.devices.push(data) - 1
+      _.assign(data, alter)
+      $rootScope.$digest()
+    }
+
+    function modify(data, properties) {
+      if (data) {
+        _.assign(data, properties)
+        $rootScope.$digest()
+      }
+    }
+
+    function remove(data) {
+      var index = deviceService.devicesBySerial[data.serial]
+      if (index >= 0) {
+        deviceService.devices.splice(index, 1)
+        delete deviceService.devicesBySerial[data.serial]
+        $rootScope.$digest()
+      }
+    }
+
+    socket.on('device.present', function(data) {
+      remove(data)
+      insert(data, {
+        present: true
+      })
+    })
+
+    socket.on('device.status', function(data) {
+      modify(get(data), data)
+    })
+
+    socket.on('device.absent', function(data) {
+      remove(data)
+    })
+
     oboe('/api/v1/devices')
       .node('devices[*]', function(device) {
-        deviceService.devices.push(device)
-        $rootScope.$digest()
+        // We want to skip other arguments
+        insert(device)
       })
 
     return deviceService