narrow: Replace pm_string() with _id and _email variants.

This makes the format returned by these functions more clear.

frontend_tests/node_tests/narrow_state.js

@@ -276,24 +276,24 @@ test("stream_sub", () => {
     assert.equal(narrow_state.stream(), undefined);
 });
 
-test("pm_string", () => {
+test("pm_ids_string", () => {
     // This function will return undefined unless we're clearly
     // narrowed to a specific PM (including huddles) with real
     // users.
     narrow_state.set_current_filter(undefined);
-    assert.equal(narrow_state.pm_string(), undefined);
+    assert.equal(narrow_state.pm_ids_string(), undefined);
 
     set_filter([
         ["stream", "Foo"],
         ["topic", "Bar"],
     ]);
-    assert.equal(narrow_state.pm_string(), undefined);
+    assert.equal(narrow_state.pm_ids_string(), undefined);
 
     set_filter([["pm-with", ""]]);
-    assert.equal(narrow_state.pm_string(), undefined);
+    assert.equal(narrow_state.pm_ids_string(), undefined);
 
     set_filter([["pm-with", "bogus@foo.com"]]);
-    assert.equal(narrow_state.pm_string(), undefined);
+    assert.equal(narrow_state.pm_ids_string(), undefined);
 
     const alice = {
         email: "alice@foo.com",
@@ -311,5 +311,5 @@ test("pm_string", () => {
     people.add_active_user(bob);
 
     set_filter([["pm-with", "bob@foo.com,alice@foo.com"]]);
-    assert.equal(narrow_state.pm_string(), "444,555");
+    assert.equal(narrow_state.pm_ids_string(), "444,555");
 });

static/js/compose_closed_ui.js

@@ -19,13 +19,13 @@ export function get_recipient_label(message) {
                     stream: narrow_state.stream(),
                     topic: narrow_state.topic(),
                 };
-            } else if (narrow_state.pm_string()) {
+            } else if (narrow_state.pm_ids_string()) {
                 // TODO: This is a total hack.  Ideally, we'd rework
                 // this to not duplicate the actual compose_actions.js
                 // logic for what happens when you click the button,
                 // and not call into random modules with hacky fake
                 // "message" objects.
-                const user_ids = people.user_ids_string_to_ids_array(narrow_state.pm_string());
+                const user_ids = people.user_ids_string_to_ids_array(narrow_state.pm_ids_string());
                 const user_ids_dicts = user_ids.map((user_id) => ({id: user_id}));
                 message = {
                     display_reply_to: message_store.get_pm_full_names({

static/js/narrow.js

@@ -860,7 +860,7 @@ export function narrow_to_next_topic() {
 }
 
 export function narrow_to_next_pm_string() {
-    const curr_pm = narrow_state.pm_string();
+    const curr_pm = narrow_state.pm_ids_string();
 
     const next_pm = topic_generator.get_next_unread_pm_string(curr_pm);
 

static/js/narrow_state.js

@@ -140,10 +140,21 @@ export function topic() {
     return undefined;
 }
 
-export function pm_string() {
+export function pm_ids_string() {
     // If you are narrowed to a PM conversation
     // with users 4, 5, and 99, this will return "4,5,99"
+    const emails_string = pm_emails_string();
 
+    if (!emails_string) {
+        return undefined;
+    }
+
+    const user_ids_string = people.reply_to_to_user_ids_string(emails_string);
+
+    return user_ids_string;
+}
+
+export function pm_emails_string() {
     if (current_filter === undefined) {
         return undefined;
     }
@@ -153,15 +164,7 @@ export function pm_string() {
         return undefined;
     }
 
-    const emails_string = operands[0];
-
-    if (!emails_string) {
-        return undefined;
-    }
-
-    const user_ids_string = people.reply_to_to_user_ids_string(emails_string);
-
-    return user_ids_string;
+    return operands[0];
 }
 
 export function get_first_unread_info() {
@@ -240,7 +243,7 @@ export function _possible_unread_message_ids() {
     }
 
     if (current_filter.can_bucket_by("pm-with")) {
-        current_filter_pm_string = pm_string();
+        current_filter_pm_string = pm_ids_string();
         if (current_filter_pm_string === undefined) {
             return [];
         }