You can't just use React classes as normal static classes :(

src/Avatar.js

@@ -0,0 +1,50 @@
+/*
+Copyright 2015 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.
+*/
+
+'use strict';
+
+var MatrixClientPeg = require('./MatrixClientPeg');
+
+module.exports = {
+    avatarUrlForMember: function(member, width, height, resizeMethod) {
+        var url = MatrixClientPeg.get().getAvatarUrlForMember(
+            member, width, height, resizeMethod, false
+        );
+        if (url === null) {
+            url = this.defaultAvatarUrlForString(member.userId);
+        }
+        return url;
+    },
+
+    defaultAvatarUrlForString: function(s) {
+        var total = 0;
+        for (var i = 0; i < s.length; ++i) {
+            total += s.charCodeAt(i);
+        }
+        switch (total % 3) {
+            case 0:
+                return "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACgAAAAoCAIAAAADnC86AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAADRJREFUeNrszQENADAIACB9QjNbxSKP4eagAFnTseHFErFYLBaLxWKxWCwWi8Vi8cX4CzAABSwCRWJw31gAAAAASUVORK5CYII=";
+                break;
+            case 1:
+                return "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACgAAAAoCAIAAAADnC86AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAADRJREFUeNrszQENADAIACB9chOaxgCP4eagAFk9seHFErFYLBaLxWKxWCwWi8Vi8cX4CzAAtKMCks/JG8MAAAAASUVORK5CYII=";
+                break;
+            case 2:
+                return "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACgAAAAoCAIAAAADnC86AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAADRJREFUeNrszQENADAIACB9YzNayQCP4eagADldseHFErFYLBaLxWKxWCwWi8Vi8cX4CzAAyiACeHwPiu4AAAAASUVORK5CYII=";
+                break;
+        }
+    }
+}
+