--- a/dom/bluetooth2/BluetoothAdapter.cpp
+++ b/dom/bluetooth2/BluetoothAdapter.cpp
@@ -848,82 +848,72 @@ BluetoothAdapter::HandleDeviceFound(cons
 
   // Notify application of discovered device via discovery handle
   mDiscoveryHandleInUse->DispatchDeviceEvent(discoveredDevice);
 }
 
 void
 BluetoothAdapter::HandleDevicePaired(const BluetoothValue& aValue)
 {
-  MOZ_ASSERT(aValue.type() == BluetoothValue::TArrayOfBluetoothNamedValue);
-
-  if (mState != BluetoothAdapterState::Enabled) {
-    BT_WARNING("HandleDevicePaired() is called when adapter isn't enabled.");
+  if (NS_WARN_IF(mState != BluetoothAdapterState::Enabled)) {
     return;
   }
 
+  MOZ_ASSERT(aValue.type() == BluetoothValue::TArrayOfBluetoothNamedValue);
+
   const InfallibleTArray<BluetoothNamedValue>& arr =
     aValue.get_ArrayOfBluetoothNamedValue();
 
   MOZ_ASSERT(arr.Length() == 3 &&
              arr[0].value().type() == BluetoothValue::TnsString && // Address
-             arr[1].value().type() == BluetoothValue::Tbool &&     // Paired
-             arr[2].value().type() == BluetoothValue::TnsString);  // Name
+             arr[1].value().type() == BluetoothValue::TnsString && // Name
+             arr[2].value().type() == BluetoothValue::Tbool);      // Paired
   MOZ_ASSERT(!arr[0].value().get_nsString().IsEmpty() &&
-             arr[1].value().get_bool());
-
-  nsString deviceAddress = arr[0].value().get_nsString();
-
-  nsRefPtr<BluetoothDevice> pairedDevice = nullptr;
+             arr[2].value().get_bool());
 
-  // Check whether or not the address exists in mDevices.
-  size_t index = mDevices.IndexOf(deviceAddress);
+  // Append the paired device if it doesn't exist in adapter's devices array
+  size_t index = mDevices.IndexOf(arr[0].value().get_nsString());
   if (index == mDevices.NoIndex) {
-    // Create a new device and append it to adapter's device array
-    pairedDevice = BluetoothDevice::Create(GetOwner(), aValue);
-    mDevices.AppendElement(pairedDevice);
-  } else {
-    // Use existing device
-    pairedDevice = mDevices[index];
+    index = mDevices.Length(); // the new device's index
+    mDevices.AppendElement(
+      BluetoothDevice::Create(GetOwner(), aValue));
   }
 
   // Notify application of paired device
   BluetoothDeviceEventInit init;
-  init.mDevice = pairedDevice;
-  DispatchDeviceEvent(NS_LITERAL_STRING("devicepaired"), init);
+  init.mDevice = mDevices[index];
+  DispatchDeviceEvent(NS_LITERAL_STRING(DEVICE_PAIRED_ID), init);
 }
 
 void
 BluetoothAdapter::HandleDeviceUnpaired(const BluetoothValue& aValue)
 {
-  MOZ_ASSERT(aValue.type() == BluetoothValue::TArrayOfBluetoothNamedValue);
-
-  if (mState != BluetoothAdapterState::Enabled) {
-    BT_WARNING("HandleDeviceUnpaired() is called when adapter isn't enabled.");
+  if (NS_WARN_IF(mState != BluetoothAdapterState::Enabled)) {
     return;
   }
 
+  MOZ_ASSERT(aValue.type() == BluetoothValue::TArrayOfBluetoothNamedValue);
+
   const InfallibleTArray<BluetoothNamedValue>& arr =
     aValue.get_ArrayOfBluetoothNamedValue();
 
   MOZ_ASSERT(arr.Length() == 2 &&
              arr[0].value().type() == BluetoothValue::TnsString && // Address
              arr[1].value().type() == BluetoothValue::Tbool);      // Paired
   MOZ_ASSERT(!arr[0].value().get_nsString().IsEmpty() &&
              !arr[1].value().get_bool());
 
+  // Remove the device with the same address
   nsString deviceAddress = arr[0].value().get_nsString();
-
-  // Remove the device with the same address
   mDevices.RemoveElement(deviceAddress);
 
   // Notify application of unpaired device
   BluetoothDeviceEventInit init;
   init.mAddress = deviceAddress;
-  DispatchDeviceEvent(NS_LITERAL_STRING("deviceunpaired"), init);
+  DispatchDeviceEvent(NS_LITERAL_STRING(DEVICE_UNPAIRED_ID), init);
 }
 
 void
 BluetoothAdapter::DispatchAttributeEvent(const nsTArray<nsString>& aTypes)
 {
   NS_ENSURE_TRUE_VOID(aTypes.Length());
 
   AutoJSAPI jsapi;

--- a/dom/bluetooth2/BluetoothAdapter.h
+++ b/dom/bluetooth2/BluetoothAdapter.h
@@ -333,28 +333,29 @@ private:
    *
    * This variable is set to the latest discovery handle when adapter just
    * starts discovery, and is reset to nullptr when discovery is stopped by
    * some adapter.
    */
   nsRefPtr<BluetoothDiscoveryHandle> mDiscoveryHandleInUse;
 
   /**
-   * Arrays of references to BluetoothDevices created by this adapter.
-   * This array is empty when adapter state is Disabled.
+   * nsRefPtr array of BluetoothDevices created by this adapter. The array is
+   * empty when adapter state is Disabled.
    *
    * Devices will be appended when
-   * 1) Enabling BT: Paired devices reported by stack.
-   * 2) Discovering: Discovered devices during discovery operation.
-   * A device won't be appended if a device object with the same
-   * address already exists.
+   *   1) adapter is enabling: Paired devices reported by stack.
+   *   2) adapter is discovering: Discovered devices during discovery operation.
+   *   3) adapter paired with a device: The paired device reported by stack.
+   * Note devices with identical address won't be appended.
    *
    * Devices will be removed when
-   * 1) Starting discovery: All unpaired devices will be removed before this
-   *    adapter starts a new discovery.
-   * 2) Disabling BT: All devices will be removed.
+   *   1) adapter is disabling: All devices will be removed.
+   *   2) adapter starts discovery: All unpaired devices will be removed before
+   *      this new discovery starts.
+   *   3) adapter unpaired with a device: The unpaired device will be removed.
    */
   nsTArray<nsRefPtr<BluetoothDevice> > mDevices;
 };
 
 END_BLUETOOTH_NAMESPACE
 
 #endif