diff --git a/frontend_tests/node_tests/message_store.js b/frontend_tests/node_tests/message_store.js
index 0039ea4535..43fc237fd3 100644
--- a/frontend_tests/node_tests/message_store.js
+++ b/frontend_tests/node_tests/message_store.js
@@ -184,6 +184,12 @@ run_test('update_booleans', () => {
     assert.equal(message.unread, true);
 });
 
+run_test('each', () => {
+    message_store.each((message) => {
+        assert(message.alerted !== undefined);
+    });
+});
+
 run_test('message_id_change', () => {
     var message = {
         sender_email: 'me@example.com',
diff --git a/static/js/message_store.js b/static/js/message_store.js
index 441d6b0b11..426e9082d6 100644
--- a/static/js/message_store.js
+++ b/static/js/message_store.js
@@ -7,6 +7,12 @@ exports.get = function get(message_id) {
     return stored_messages[message_id];
 };
 
+exports.each = function (f) {
+    _.each(stored_messages, function (message) {
+        f(message);
+    });
+};
+
 exports.get_pm_emails = function (message) {
 
     function email(user_id) {