Update client deps: react 16.3, babel 7

client/src/js/utils/createReducer.js

@@ -0,0 +1,8 @@
+export default function createReducer(initialState, handlers) {
+  return function reducer(state = initialState, action) {
+    if (Object.prototype.hasOwnProperty.call(handlers, action.type)) {
+      return handlers[action.type](state, action);
+    }
+    return state;
+  };
+}