Make the function call-rate limiting a generic thing and use it in more places.

src/components/structures/RoomView.js

@@ -41,6 +41,7 @@ var Resend = require("../../Resend");
 var SlashCommands = require("../../SlashCommands");
 var dis = require("../../dispatcher");
 var Tinter = require("../../Tinter");
+var rate_limited_func = require('../../ratelimitedfunc');
 
 var PAGINATE_SIZE = 20;
 var INITIAL_SIZE = 20;
@@ -617,7 +618,7 @@ module.exports = React.createClass({
         }
     },
 
-    _updateTabCompleteList: function(room) {
+    _updateTabCompleteList: new rate_limited_func(function(room) {
         if (!room || !this.tabComplete) {
             return;
         }
@@ -626,7 +627,7 @@ module.exports = React.createClass({
                 CommandEntry.fromCommands(SlashCommands.getCommandList())
             )
         );
-    },
+    }, 500),
 
     _initialiseMessagePanel: function() {
         var messagePanel = ReactDOM.findDOMNode(this.refs.messagePanel);

src/components/views/rooms/MemberList.js

@@ -22,6 +22,7 @@ var Modal = require("../../../Modal");
 var Entities = require("../../../Entities");
 var sdk = require('../../../index');
 var GeminiScrollbar = require('react-gemini-scrollbar');
+var rate_limited_func = require('../../../ratelimitedfunc');
 
 var INITIAL_LOAD_NUM_MEMBERS = 30;
 var SHARE_HISTORY_WARNING = "Newly invited users will see the history of this room. "+
@@ -147,14 +148,14 @@ module.exports = React.createClass({
         }
     },
 
-    _updateList: function() {
+    _updateList: new rate_limited_func(function() {
         this.memberDict = this.getMemberDict();
 
         var self = this;
         this.setState({
             members: self.roomMembers()
         });
-    },
+    }, 500),
 
     onInvite: function(inputText) {
         var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");

src/components/views/rooms/RoomList.js

@@ -24,6 +24,7 @@ var RoomListSorter = require("../../../RoomListSorter");
 var Unread = require('../../../Unread');
 var dis = require("../../../dispatcher");
 var sdk = require('../../../index');
+var rate_limited_func = require('../../../ratelimitedfunc');
 
 var HIDE_CONFERENCE_CHANS = true;
 
@@ -155,36 +156,9 @@ module.exports = React.createClass({
         this._delayedRefreshRoomList();
     },
 
-    _delayedRefreshRoomList: function() {
-        // There can be 1000s of JS SDK events when rooms are initially synced;
-        // we don't want to do lots of work rendering until things have settled.
-        // Therefore, keep a 1s refresh buffer which will refresh the room list
-        // at MOST once every 1s to prevent thrashing.
-        var MAX_REFRESH_INTERVAL_MS = 1000;
-        var self = this;
-
-        if (!self._lastRefreshRoomListTs) {
-            self.refreshRoomList(); // first refresh evar
-        }
-        else {
-            var timeWaitedMs = Date.now() - self._lastRefreshRoomListTs;
-            if (timeWaitedMs > MAX_REFRESH_INTERVAL_MS) {
-                clearTimeout(self._refreshRoomListTimerId);
-                self._refreshRoomListTimerId = null;
-                self.refreshRoomList(); // refreshed more than MAX_REFRESH_INTERVAL_MS ago
-            }
-            else {
-                // refreshed less than MAX_REFRESH_INTERVAL_MS ago, wait the difference
-                // if we aren't already waiting. If we are waiting then NOP, it will
-                // fire soon, promise!
-                if (!self._refreshRoomListTimerId) {
-                    self._refreshRoomListTimerId = setTimeout(function() {
-                        self.refreshRoomList();
-                    }, 10 + MAX_REFRESH_INTERVAL_MS - timeWaitedMs); // 10 is a buffer amount
-                }
-            }
-        }
-    },
+    _delayedRefreshRoomList: new rate_limited_func(function() {
+        this.refreshRoomList();
+    }, 500),
 
     refreshRoomList: function() {
         // console.log("DEBUG: Refresh room list delta=%s ms",

src/ratelimitedfunc.js

@@ -0,0 +1,39 @@
+/*
+Copyright 2016 OpenMarket Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+module.exports = function(f, min_interval_ms) {
+    this.lastCall = 0;
+    this.scheduledCall = undefined;
+
+    var self = this;
+    return function() {
+        var now = Date.now();
+
+        if (self.lastCall < now - min_interval_ms) {
+            f.apply(this);
+            self.lastCall = now;
+        } else if (self.scheduledCall === undefined) {
+            self.scheduledCall = setTimeout(() => {
+                    self.scheduledCall = undefined;
+                    f.apply(this);
+                    self.lastCall = now;
+                },
+                (self.lastCall + min_interval_ms) - now
+            );
+        }
+    };
+};
+