echo: Extract the waiting for id and ack into separate module.

This commit extracts the "waiting_for_id" and "waiting_for_ack"
data structures of "echo.js" into a separate module in "echo_state".

This is a preparatory commit so as to be able to use them for
"stream_topic_history" module, without causing import cycles.

web/src/echo.ts

@@ -7,6 +7,7 @@ import {all_messages_data} from "./all_messages_data";
 import * as blueslip from "./blueslip";
 import * as compose_notifications from "./compose_notifications";
 import * as compose_ui from "./compose_ui";
+import * as echo_state from "./echo_state";
 import * as local_message from "./local_message";
 import * as markdown from "./markdown";
 import * as message_events_util from "./message_events_util";
@@ -95,9 +96,6 @@ type LocalMessage = MessageRequestObject & {
 
 type PostMessageAPIData = z.output<typeof send_message_api_response_schema>;
 
-const waiting_for_id = new Map<string, Message>();
-let waiting_for_ack = new Map<string, Message>();
-
 // These retry spinner functions return true if and only if the
 // spinner already is in the requested state, which can be used to
 // avoid sending duplicate requests.
@@ -273,8 +271,8 @@ export function insert_local_message(
     const [message] = insert_new_messages([local_message], true, true);
     assert(message !== undefined);
     assert(message.local_id !== undefined);
-    waiting_for_id.set(message.local_id, message);
-    waiting_for_ack.set(message.local_id, message);
+    echo_state.set_message_waiting_for_id(message.local_id, message);
+    echo_state.set_message_waiting_for_ack(message.local_id, message);
 
     return message;
 }
@@ -428,8 +426,8 @@ export function edit_locally(message: Message, request: LocalEditRequest): Messa
 }
 
 export function reify_message_id(local_id: string, server_id: number): void {
-    const message = waiting_for_id.get(local_id);
-    waiting_for_id.delete(local_id);
+    const message = echo_state.get_message_waiting_for_id(local_id);
+    echo_state.remove_message_from_waiting_for_id(local_id);
 
     // reify_message_id is called both on receiving a self-sent message
     // from the server, and on receiving the response to the send request
@@ -481,7 +479,7 @@ export function process_from_server(messages: ServerMessage[]): ServerMessage[]
             continue;
         }
 
-        const client_message = waiting_for_ack.get(local_id);
+        const client_message = echo_state.get_message_waiting_for_ack(local_id);
         if (client_message === undefined) {
             non_echo_messages.push(message);
             continue;
@@ -519,7 +517,7 @@ export function process_from_server(messages: ServerMessage[]): ServerMessage[]
         client_message.submessages = message.submessages;
 
         msgs_to_rerender_or_add_to_narrow.push(client_message);
-        waiting_for_ack.delete(local_id);
+        echo_state.remove_message_from_waiting_for_ack(local_id);
     }
 
     if (msgs_to_rerender_or_add_to_narrow.length > 0) {
@@ -547,11 +545,6 @@ export function process_from_server(messages: ServerMessage[]): ServerMessage[]
     return non_echo_messages;
 }
 
-export function _patch_waiting_for_ack(data: Map<string, Message>): void {
-    // Only for testing
-    waiting_for_ack = data;
-}
-
 export function message_send_error(message_id: number, error_response: string): void {
     // Error sending message, show inline
     const message = message_store.get(message_id)!;
@@ -616,7 +609,7 @@ export function initialize({
             const local_id = rows.local_echo_id($row);
             // Message should be waiting for ack and only have a local id,
             // otherwise send would not have failed
-            const message = waiting_for_ack.get(local_id);
+            const message = echo_state.get_message_waiting_for_ack(local_id);
             if (message === undefined) {
                 blueslip.warn(
                     "Got resend or retry on failure request but did not find message in ack list " +

web/src/echo_state.ts

@@ -0,0 +1,33 @@
+import type {Message} from "./message_store";
+
+const waiting_for_id = new Map<string, Message>();
+let waiting_for_ack = new Map<string, Message>();
+
+export function set_message_waiting_for_id(local_id: string, message: Message): void {
+    waiting_for_id.set(local_id, message);
+}
+
+export function set_message_waiting_for_ack(local_id: string, message: Message): void {
+    waiting_for_ack.set(local_id, message);
+}
+
+export function get_message_waiting_for_id(local_id: string): Message | undefined {
+    return waiting_for_id.get(local_id);
+}
+
+export function get_message_waiting_for_ack(local_id: string): Message | undefined {
+    return waiting_for_ack.get(local_id);
+}
+
+export function remove_message_from_waiting_for_id(local_id: string): void {
+    waiting_for_id.delete(local_id);
+}
+
+export function remove_message_from_waiting_for_ack(local_id: string): void {
+    waiting_for_ack.delete(local_id);
+}
+
+export function _patch_waiting_for_ack(data: Map<string, Message>): void {
+    // Only for testing
+    waiting_for_ack = data;
+}

web/tests/echo.test.js

@@ -67,6 +67,7 @@ const home_msg_list = {
 message_lists.all_rendered_message_lists = () => [home_msg_list, message_lists.current];
 
 const echo = zrequire("echo");
+const echo_state = zrequire("echo_state");
 const people = zrequire("people");
 const stream_data = zrequire("stream_data");
 
@@ -84,7 +85,7 @@ run_test("process_from_server for un-echoed messages", () => {
             local_id: "100.1",
         },
     ];
-    echo._patch_waiting_for_ack(waiting_for_ack);
+    echo_state._patch_waiting_for_ack(waiting_for_ack);
     const non_echo_messages = echo.process_from_server(server_messages);
     assert.deepEqual(non_echo_messages, server_messages);
 });
@@ -122,7 +123,7 @@ run_test("process_from_server for differently rendered messages", ({override}) =
             topic_links: new_value,
         },
     ];
-    echo._patch_waiting_for_ack(waiting_for_ack);
+    echo_state._patch_waiting_for_ack(waiting_for_ack);
     disparities = [];
     const non_echo_messages = echo.process_from_server(server_messages);
     assert.deepEqual(non_echo_messages, []);
@@ -171,7 +172,7 @@ run_test("process_from_server for messages to add to narrow", ({override}) => {
             topic_links: new_value,
         },
     ];
-    echo._patch_waiting_for_ack(waiting_for_ack);
+    echo_state._patch_waiting_for_ack(waiting_for_ack);
     const non_echo_messages = echo.process_from_server(server_messages);
     assert.deepEqual(non_echo_messages, []);
     assert.deepEqual(messages_to_add_to_narrow, [