ts: Convert user_groups module to TypeScript.

frontend_tests/node_tests/composebox_typeahead.js

@@ -256,21 +256,21 @@ const hamletcharacters = {
     name: "hamletcharacters",
     id: 1,
     description: "Characters of Hamlet",
-    members: [100, 104],
+    members: new Set([100, 104]),
 };
 
 const backend = {
     name: "Backend",
     id: 2,
     description: "Backend team",
-    members: [],
+    members: new Set([]),
 };
 
 const call_center = {
     name: "Call Center",
     id: 3,
     description: "folks working in support",
-    members: [],
+    members: new Set([]),
 };
 
 const make_emoji = (emoji_dict) => ({

frontend_tests/node_tests/user_groups.js

@@ -10,9 +10,10 @@ const user_groups = zrequire("user_groups");
 
 run_test("user_groups", () => {
     const students = {
+        description: "Students group",
         name: "Students",
         id: 0,
-        members: [1, 2],
+        members: new Set([1, 2]),
     };
 
     const params = {};
@@ -21,22 +22,22 @@ run_test("user_groups", () => {
     const user_id_part_of_a_group = 2;
 
     user_groups.initialize(params);
-    assert.equal(user_groups.get_user_group_from_id(students.id), students);
+    assert.deepEqual(user_groups.get_user_group_from_id(students.id), students);
 
     const admins = {
         name: "Admins",
         description: "foo",
         id: 1,
-        members: [3],
+        members: new Set([3]),
     };
     const all = {
         name: "Everyone",
         id: 2,
-        members: [1, 2, 3],
+        members: new Set([1, 2, 3]),
     };
 
     user_groups.add(admins);
-    assert.equal(user_groups.get_user_group_from_id(admins.id), admins);
+    assert.deepEqual(user_groups.get_user_group_from_id(admins.id), admins);
 
     const update_name_event = {
         group_id: admins.id,
@@ -104,4 +105,8 @@ run_test("user_groups", () => {
 
     blueslip.expect("error", "Could not find user group with ID -1");
     assert.equal(user_groups.is_member_of(-1, 15), false);
+
+    blueslip.expect("error", "Could not find user group with ID -9999", 2);
+    user_groups.add_members(-9999);
+    user_groups.remove_members(-9999);
 });

static/js/types.ts

@@ -0,0 +1,14 @@
+// TODO/typescript: Move this to server_events_dispatch
+export type UserGroupUpdateEvent = {
+    id: number;
+    type: string;
+    group_id: number;
+    data: {
+        name?: string;
+        description?: string;
+    };
+};
+
+// TODO/typescript: Move the User and Stream placeholder
+// types to their approriate modules.
+export type User = Record<string, never>;

static/js/user_groups.ts

@@ -1,32 +1,50 @@
 import * as blueslip from "./blueslip";
 import {FoldDict} from "./fold_dict";
+import type {User, UserGroupUpdateEvent} from "./types";
 
-let user_group_name_dict;
-let user_group_by_id_dict;
+type UserGroup = {
+    description: string;
+    id: number;
+    name: string;
+    members: Set<number>;
+};
+
+// The members field is a number array which we convert
+// to a Set in the initialize function.
+type UserGroupRaw = Omit<UserGroup, "members"> & {members: number[]};
+
+let user_group_name_dict: FoldDict<UserGroup>;
+let user_group_by_id_dict: Map<number, UserGroup>;
 
 // We have an init() function so that our automated tests
 // can easily clear data.
-export function init() {
+export function init(): void {
     user_group_name_dict = new FoldDict();
-    user_group_by_id_dict = new Map();
+    user_group_by_id_dict = new Map<number, UserGroup>();
 }
 
 // WE INITIALIZE DATA STRUCTURES HERE!
 init();
 
-export function add(user_group) {
+export function add(user_group_raw: UserGroupRaw): void {
     // Reformat the user group members structure to be a set.
-    user_group.members = new Set(user_group.members);
+    const user_group = {
+        description: user_group_raw.description,
+        id: user_group_raw.id,
+        name: user_group_raw.name,
+        members: new Set(user_group_raw.members),
+    };
+
     user_group_name_dict.set(user_group.name, user_group);
     user_group_by_id_dict.set(user_group.id, user_group);
 }
 
-export function remove(user_group) {
+export function remove(user_group: UserGroup): void {
     user_group_name_dict.delete(user_group.name);
     user_group_by_id_dict.delete(user_group.id);
 }
 
-export function get_user_group_from_id(group_id) {
+export function get_user_group_from_id(group_id: number): UserGroup {
     const user_group = user_group_by_id_dict.get(group_id);
     if (!user_group) {
         throw new Error("Unknown group_id in get_user_group_from_id: " + group_id);
@@ -34,7 +52,7 @@ export function get_user_group_from_id(group_id) {
     return user_group;
 }
 
-export function update(event) {
+export function update(event: UserGroupUpdateEvent): void {
     const group = get_user_group_from_id(event.group_id);
     if (event.data.name !== undefined) {
         group.name = event.data.name;
@@ -48,16 +66,16 @@ export function update(event) {
     }
 }
 
-export function get_user_group_from_name(name) {
+export function get_user_group_from_name(name: string): UserGroup | undefined {
     return user_group_name_dict.get(name);
 }
 
-export function get_realm_user_groups() {
+export function get_realm_user_groups(): UserGroup[] {
     const user_groups = Array.from(user_group_by_id_dict.values()).sort((a, b) => a.id - b.id);
     return user_groups.filter((group) => !group.is_system_group);
 }
 
-export function is_member_of(user_group_id, user_id) {
+export function is_member_of(user_group_id: number, user_id: number): boolean {
     const user_group = user_group_by_id_dict.get(user_group_id);
     if (user_group === undefined) {
         blueslip.error("Could not find user group with ID " + user_group_id);
@@ -66,33 +84,41 @@ export function is_member_of(user_group_id, user_id) {
     return user_group.members.has(user_id);
 }
 
-export function add_members(user_group_id, user_ids) {
+export function add_members(user_group_id: number, user_ids: number[]): void {
     const user_group = user_group_by_id_dict.get(user_group_id);
+    if (user_group === undefined) {
+        blueslip.error("Could not find user group with ID " + user_group_id);
+        return;
+    }
 
     for (const user_id of user_ids) {
         user_group.members.add(user_id);
     }
 }
 
-export function remove_members(user_group_id, user_ids) {
+export function remove_members(user_group_id: number, user_ids: number[]): void {
     const user_group = user_group_by_id_dict.get(user_group_id);
+    if (user_group === undefined) {
+        blueslip.error("Could not find user group with ID " + user_group_id);
+        return;
+    }
 
     for (const user_id of user_ids) {
         user_group.members.delete(user_id);
     }
 }
 
-export function initialize(params) {
+export function initialize(params: {realm_user_groups: UserGroupRaw[]}): void {
     for (const user_group of params.realm_user_groups) {
         add(user_group);
     }
 }
 
-export function is_user_group(item) {
+export function is_user_group(item: User | UserGroup): item is UserGroup {
     return item.members !== undefined;
 }
 
-export function get_user_groups_of_user(user_id) {
+export function get_user_groups_of_user(user_id: number): UserGroup[] {
     const user_groups_realm = get_realm_user_groups();
     const groups_of_user = user_groups_realm.filter((group) => is_member_of(group.id, user_id));
     return groups_of_user;

tools/test-js-with-node

@@ -168,6 +168,7 @@ EXEMPT_FILES = {
     "static/js/topic_list.js",
     "static/js/topic_zoom.js",
     "static/js/tutorial.js",
+    "static/js/types.ts",
     "static/js/typing_events.js",
     "static/js/typing.js",
     "static/js/ui_init.js",