docs: Add more details on Mopidy.js calling convention

docs/api/js.rst

@@ -129,7 +129,14 @@ When creating an instance, you can specify the following settings:
     Using named arguments also makes the code more readable, and more resistent
     to future API changes.
 
-    For backwards compatibility, the default is "by-position-only".
+    .. note::
+
+        For backwards compatibility, the default is "by-position-only". In the
+        future, the default will change to "by-position-or-by-name". You should
+        explicitly set this setting to your choice, so you won't be affected
+        when the default changes.
+
+    .. versionadded:: 0.19 (Mopidy.js 0.4)
 
 ``webSocket``
     An existing WebSocket object to be used instead of creating a new

docs/changelog.rst

@@ -78,6 +78,8 @@ Feature release.
   Mopidy's HTTP server among other Zeroconf-published HTTP servers on the
   local network.
 
+**Mopidy.js client library**
+
 - Update Mopidy.js to use when.js 3. If you maintain a Mopidy client, you
   should review the `differences between when.js 2 and 3
   <https://github.com/cujojs/when/blob/master/docs/api.md#upgrading-to-30-from-2x>`_
@@ -93,8 +95,8 @@ Feature release.
   ``Mopidy.ConnectionError``.
 
 - Add support for method calls with by-name arguments. The old calling
-  convention, by-position-only, is still the default. See the :ref:`mopidy-js`
-  docs for details.
+  convention, ``by-position-only``, is still the default, but this will
+  probably change in the future. See the :ref:`mopidy-js` docs for details.
 
 **MPD frontend**
 

js/README.md

@@ -83,7 +83,8 @@ Changelog
 ### 0.4.0 (UNRELEASED)
 
 - Add support for method calls with by-name arguments. The old calling
-  convention, by-position-only, is still the default. See the docs for details.
+  convention, "by-position-only", is still the default, but this will change in
+  the future. See the docs for details.
 
 ### 0.3.0 (2014-06-16)