diff --git a/static/js/typing.js b/static/js/typing.js
index 932644efbd..5bd1cc0f0c 100644
--- a/static/js/typing.js
+++ b/static/js/typing.js
@@ -7,12 +7,11 @@ var exports = {};
 //
 // See docs/subsystems/typing-indicators.md for details on typing indicators.
 
-function send_typing_notification_ajax(user_ids_string, operation) {
-    var typing_to = people.user_ids_string_to_emails_string(user_ids_string);
+function send_typing_notification_ajax(user_ids_array, operation) {
     channel.post({
         url: '/json/typing',
         data: {
-            to: typing_to,
+            to: JSON.stringify(user_ids_array),
             op: operation,
         },
         success: function () {},
@@ -22,13 +21,13 @@ function send_typing_notification_ajax(user_ids_string, operation) {
     });
 }
 
-function get_user_ids_string() {
+function get_user_ids_array() {
     var user_ids_string = compose_pm_pill.get_user_ids_string();
-
     if (user_ids_string === "") {
         return;
     }
-    return user_ids_string;
+
+    return people.user_ids_string_to_ids_array(user_ids_string);
 }
 
 function is_valid_conversation(user_ids_string) {
@@ -73,7 +72,7 @@ function notify_server_stop(user_ids_string) {
 
 exports.initialize = function () {
     var worker = {
-        get_recipient: get_user_ids_string,
+        get_recipient: get_user_ids_array,
         is_valid_conversation: is_valid_conversation,
         get_current_time: get_current_time,
         notify_server_start: notify_server_start,
diff --git a/static/js/typing_status.js b/static/js/typing_status.js
index 8fa4a4fd8d..84a7a89dd1 100644
--- a/static/js/typing_status.js
+++ b/static/js/typing_status.js
@@ -91,7 +91,9 @@ exports.handle_text_input = function (worker) {
     var current_recipient = exports.state.current_recipient;
 
     if (current_recipient) {
-        if (new_recipient === current_recipient) {
+        // We need to use _.isEqual for comparisons; === doesn't work
+        // on arrays.
+        if (_.isEqual(new_recipient, current_recipient)) {
             // Nothing has really changed, except we may need
             // to send a ping to the server.
             maybe_ping_server(worker, new_recipient);
@@ -106,7 +108,6 @@ exports.handle_text_input = function (worker) {
         // so we must stop the old notification.  Don't return
         // yet, because we may have a new recipient.
         stop_last_notification(worker);
-
     }
 
     if (!worker.is_valid_conversation(new_recipient)) {