Refactor to allow dispatching of two kinds of Actions

They are:
 1. The existing type of Action, Objects with an `action` type.
 1. Asyncronous Actions, functions that accept a `dispatch` argument, which can be used to dispatch Actions asyncronously.

src/actions/GroupActions.js

@@ -14,13 +14,12 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { createPromiseActionCreator } from './actionCreators';
+import { asyncAction } from './actionCreators';
 
 const GroupActions = {};
 
-GroupActions.fetchJoinedGroups = createPromiseActionCreator(
-    'GroupActions.fetchJoinedGroups',
-    (matrixClient) => matrixClient.getJoinedGroups(),
-);
+GroupActions.fetchJoinedGroups = function(matrixClient) {
+    return asyncAction('GroupActions.fetchJoinedGroups', () => matrixClient.getJoinedGroups());
+};
 
 export default GroupActions;

src/actions/TagOrderActions.js

@@ -15,14 +15,13 @@ limitations under the License.
 */
 
 import Analytics from '../Analytics';
-import { createPromiseActionCreator } from './actionCreators';
+import { asyncAction } from './actionCreators';
 import TagOrderStore from '../stores/TagOrderStore';
 
 const TagOrderActions = {};
 
-TagOrderActions.commitTagOrdering = createPromiseActionCreator(
-    'TagOrderActions.commitTagOrdering',
-    (matrixClient) => {
+TagOrderActions.commitTagOrdering = function(matrixClient) {
+    return asyncAction('TagOrderActions.commitTagOrdering', () => {
         // Only commit tags if the state is ready, i.e. not null
         const tags = TagOrderStore.getOrderedTags();
         if (!tags) {
@@ -31,7 +30,7 @@ TagOrderActions.commitTagOrdering = createPromiseActionCreator(
 
         Analytics.trackEvent('TagOrderActions', 'commitTagOrdering');
         return matrixClient.setAccountData('im.vector.web.tag_ordering', {tags});
-    },
-);
+    });
+};
 
 export default TagOrderActions;

src/actions/actionCreators.js

@@ -14,25 +14,23 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import dis from '../dispatcher';
-
 /**
- * Create an action creator that will dispatch actions asynchronously that
- * indicate the current status of promise returned by the given function, fn.
+ * Create an asynchronous action creator that will dispatch actions indicating
+ * the current status of the promise returned by fn.
  * @param {string} id the id to give the dispatched actions. This is given a
- *                   suffix determining whether it is pending, successful or
- *                   a failure.
- * @param {function} fn the function to call with arguments given to the
- *                   returned function. This function should return a Promise.
- * @returns {function} a function that dispatches asynchronous actions when called.
+ *                    suffix determining whether it is pending, successful or
+ *                    a failure.
+ * @param {function} fn a function that returns a Promise.
+ * @returns {function} a function that uses its single argument as a dispatch
+ *                     function.
  */
-export function createPromiseActionCreator(id, fn) {
-    return (...args) => {
-        dis.dispatch({action: id + '.pending'});
-        fn(...args).then((result) => {
-            dis.dispatch({action: id + '.success', result});
+export function asyncAction(id, fn) {
+    return (dispatch) => {
+        dispatch({action: id + '.pending'});
+        fn().then((result) => {
+            dispatch({action: id + '.success', result});
         }).catch((err) => {
-            dis.dispatch({action: id + '.failure', err});
+            dispatch({action: id + '.failure', err});
         });
     };
 }

src/components/structures/TagPanel.js

@@ -68,7 +68,7 @@ const TagPanel = React.createClass({
             });
         });
         // This could be done by anything with a matrix client
-        GroupActions.fetchJoinedGroups(this.context.matrixClient);
+        dis.dispatch(GroupActions.fetchJoinedGroups(this.context.matrixClient));
     },
 
     componentWillUnmount() {
@@ -81,7 +81,7 @@ const TagPanel = React.createClass({
 
     _onGroupMyMembership() {
         if (this.unmounted) return;
-        GroupActions.fetchJoinedGroups(this.context.matrixClient);
+        dis.dispatch(GroupActions.fetchJoinedGroups.bind(this.context.matrixClient));
     },
 
     onClick() {
@@ -94,7 +94,7 @@ const TagPanel = React.createClass({
     },
 
     onTagTileEndDrag() {
-        TagOrderActions.commitTagOrdering(this.context.matrixClient);
+        dis.dispatch(TagOrderActions.commitTagOrdering(this.context.matrixClient));
     },
 
     render() {

src/dispatcher.js

@@ -20,14 +20,24 @@ const flux = require("flux");
 
 class MatrixDispatcher extends flux.Dispatcher {
     /**
-     * @param {Object} payload Required. The payload to dispatch.
-     *        Must contain at least an 'action' key.
+     * @param {Object|function} payload Required. The payload to dispatch.
+     *        If an Object, must contain at least an 'action' key.
+     *        If a function, must have the signature (dispatch) => {...}.
      * @param {boolean=} sync Optional. Pass true to dispatch
      *        synchronously. This is useful for anything triggering
      *        an operation that the browser requires user interaction
      *        for.
      */
     dispatch(payload, sync) {
+        // Allow for asynchronous dispatching by accepting payloads that have the
+        // type `function (dispatch) {...}`
+        if (typeof payload === 'function') {
+            payload((action) => {
+                this.dispatch(action, sync);
+            });
+            return;
+        }
+
         if (sync) {
             super.dispatch(payload);
         } else {