stream_data: Refactored function to return sub and can_sub streams.

This commit refactors the 'get_subscribed_streams_for_user' function
to return an object with two keys: one for the subscribed streams
and another for the streams the user can subscribe to. The node
tests have been updated accordingly.

Renamed 'get_subscribed_streams_for_user' to 'get_streams_for_user'.

web/src/stream_data.ts

@@ -388,11 +388,15 @@ export function muted_stream_ids(): number[] {
         .map((sub) => sub.stream_id);
 }
 
-export function get_subscribed_streams_for_user(user_id: number): StreamSubscription[] {
+export function get_streams_for_user(user_id: number): {
+    subscribed: StreamSubscription[];
+    can_subscribe: StreamSubscription[];
+} {
     // Note that we only have access to subscribers of some streams
     // depending on our role.
     const all_subs = get_unsorted_subs();
     const subscribed_subs = [];
+    const can_subscribe_subs = [];
     for (const sub of all_subs) {
         if (!can_view_subscribers(sub)) {
             // Private streams that we have been removed from appear
@@ -402,10 +406,15 @@ export function get_subscribed_streams_for_user(user_id: number): StreamSubscrip
         }
         if (is_user_subscribed(sub.stream_id, user_id)) {
             subscribed_subs.push(sub);
+        } else if (can_subscribe_others(sub)) {
+            can_subscribe_subs.push(sub);
         }
     }
 
-    return subscribed_subs;
+    return {
+        subscribed: subscribed_subs,
+        can_subscribe: can_subscribe_subs,
+    };
 }
 
 export function get_invite_stream_data(): InviteStreamData[] {

web/src/user_profile.js

@@ -197,7 +197,7 @@ export function show_user_profile(user, default_tab_key = "profile-tab") {
     const profile_data = page_params.custom_profile_fields
         .map((f) => get_custom_profile_field_data(user, f, field_types))
         .filter((f) => f.name !== undefined);
-    const user_streams = stream_data.get_subscribed_streams_for_user(user.user_id);
+    const user_streams = stream_data.get_streams_for_user(user.user_id).subscribed;
     const groups_of_user = user_groups.get_user_groups_of_user(user.user_id);
     const args = {
         user_id: user.user_id,

web/tests/stream_data.test.js

@@ -201,7 +201,7 @@ test("basics", () => {
     ]);
 });
 
-test("get_subscribed_streams_for_user", () => {
+test("get_streams_for_user", () => {
     const denmark = {
         subscribed: true,
         color: "blue",
@@ -227,7 +227,16 @@ test("get_subscribed_streams_for_user", () => {
         is_muted: true,
         invite_only: true,
     };
-    const subs = [denmark, social, test];
+    const world = {
+        color: "blue",
+        name: "world",
+        stream_id: 4,
+        is_muted: false,
+        invite_only: false,
+        history_public_to_subscribers: false,
+        stream_post_policy: stream_data.stream_post_policy_values.admins.code,
+    };
+    const subs = [denmark, social, test, world];
     for (const sub of subs) {
         stream_data.add_sub(sub);
     }
@@ -235,6 +244,7 @@ test("get_subscribed_streams_for_user", () => {
     peer_data.set_subscribers(denmark.stream_id, [me.user_id, test_user.user_id]);
     peer_data.set_subscribers(social.stream_id, [test_user.user_id]);
     peer_data.set_subscribers(test.stream_id, [test_user.user_id]);
+    peer_data.set_subscribers(world.stream_id, [me.user_id]);
 
     // test_user is subscribed to all three streams, but current user (me)
     // gets only two because of subscriber visibility policy of stream:
@@ -243,10 +253,15 @@ test("get_subscribed_streams_for_user", () => {
     //          user is a guest.
     // #test: current user is no longer subscribed to a private stream, so
     //        he can not see whether test_user is subscribed to it.
-    assert.deepEqual(stream_data.get_subscribed_streams_for_user(test_user.user_id), [
+    assert.deepEqual(stream_data.get_streams_for_user(test_user.user_id).subscribed, [
         denmark,
         social,
     ]);
+    assert.deepEqual(stream_data.get_streams_for_user(test_user.user_id).can_subscribe, []);
+    // Verify can subscribe if we're an administrator.
+    page_params.is_admin = true;
+    assert.deepEqual(stream_data.get_streams_for_user(test_user.user_id).can_subscribe, [world]);
+    page_params.is_admin = false;
 });
 
 test("renames", () => {