user_groups: Add subgroups field to user group objects.

frontend_tests/node_tests/composebox_typeahead.js

@@ -291,6 +291,7 @@ const hamletcharacters = {
     description: "Characters of Hamlet",
     members: new Set([100, 104]),
     is_system_group: false,
+    subgroups: new Set([10, 11]),
 };
 
 const backend = {
@@ -299,6 +300,7 @@ const backend = {
     description: "Backend team",
     members: new Set([]),
     is_system_group: false,
+    subgroups: new Set([]),
 };
 
 const call_center = {
@@ -307,6 +309,7 @@ const call_center = {
     description: "folks working in support",
     members: new Set([]),
     is_system_group: false,
+    subgroups: new Set([]),
 };
 
 const make_emoji = (emoji_dict) => ({

frontend_tests/node_tests/user_groups.js

@@ -15,6 +15,7 @@ run_test("user_groups", () => {
         id: 0,
         members: new Set([1, 2]),
         is_system_group: false,
+        subgroups: new Set([4, 5]),
     };
 
     const params = {};
@@ -31,12 +32,14 @@ run_test("user_groups", () => {
         id: 1,
         members: new Set([3]),
         is_system_group: false,
+        subgroups: new Set([]),
     };
     const all = {
         name: "Everyone",
         id: 2,
         members: new Set([1, 2, 3]),
         is_system_group: false,
+        subgroups: new Set([4, 5, 6]),
     };
 
     user_groups.add(admins);

static/js/user_groups.ts

@@ -8,6 +8,7 @@ type UserGroup = {
     name: string;
     members: Set<number>;
     is_system_group: boolean;
+    subgroups: Set<number>;
 };
 
 // The members field is a number array which we convert
@@ -35,6 +36,7 @@ export function add(user_group_raw: UserGroupRaw): void {
         name: user_group_raw.name,
         members: new Set(user_group_raw.members),
         is_system_group: user_group_raw.is_system_group,
+        subgroups: new Set(user_group_raw.subgroups),
     };
 
     user_group_name_dict.set(user_group.name, user_group);