channel_folders: Add support for channel folders in webapp.

This commit adds code to handle channel folders data in
webapp.

web/src/channel_folders.ts

@@ -0,0 +1,34 @@
+import type {z} from "zod";
+
+import {FoldDict} from "./fold_dict.ts";
+import type {StateData, channel_folder_schema} from "./state_data.ts";
+
+export type ChannelFolder = z.infer<typeof channel_folder_schema>;
+
+let channel_folder_name_dict: FoldDict<ChannelFolder>;
+let channel_folder_by_id_dict: Map<number, ChannelFolder>;
+
+export function add(channel_folder: ChannelFolder): void {
+    channel_folder_name_dict.set(channel_folder.name, channel_folder);
+    channel_folder_by_id_dict.set(channel_folder.id, channel_folder);
+}
+
+export function initialize(params: StateData["channel_folders"]): void {
+    channel_folder_name_dict = new FoldDict();
+    channel_folder_by_id_dict = new Map<number, ChannelFolder>();
+
+    for (const channel_folder of params.channel_folders) {
+        add(channel_folder);
+    }
+}
+
+export function get_channel_folders(include_archived = false): ChannelFolder[] {
+    const channel_folders = [...channel_folder_by_id_dict.values()].sort((a, b) => a.id - b.id);
+    return channel_folders.filter((channel_folder) => {
+        if (!include_archived && channel_folder.is_archived) {
+            return false;
+        }
+
+        return true;
+    });
+}

web/src/state_data.ts

@@ -141,6 +141,15 @@ export const raw_user_group_schema = z.object({
     deactivated: z.boolean(),
 });
 
+export const channel_folder_schema = z.object({
+    id: z.number(),
+    name: z.string(),
+    rendered_description: z.string(),
+    creator_id: z.number().nullable(),
+    date_created: z.number(),
+    is_archived: z.boolean(),
+});
+
 export const user_topic_schema = z.object({
     stream_id: z.number(),
     topic_name: z.string(),
@@ -499,6 +508,11 @@ export const state_data_schema = z
             .object({realm_user_groups: z.array(raw_user_group_schema)})
             .transform((user_groups) => ({user_groups})),
     )
+    .and(
+        z
+            .object({channel_folders: z.array(channel_folder_schema)})
+            .transform((channel_folders) => ({channel_folders})),
+    )
     .and(
         z
             .object({

web/src/ui_init.js

@@ -21,6 +21,7 @@ import * as banners from "./banners.ts";
 import * as blueslip from "./blueslip.ts";
 import * as bot_data from "./bot_data.ts";
 import * as channel from "./channel.ts";
+import * as channel_folders from "./channel_folders.ts";
 import * as click_handlers from "./click_handlers.ts";
 import * as color_picker_popover from "./color_picker_popover.ts";
 import * as common from "./common.ts";
@@ -475,6 +476,9 @@ export async function initialize_everything(state_data) {
     // user_group whose members are allowed to create multiuse invite.
     user_groups.initialize(state_data.user_groups);
 
+    // Channel folders data must be initialized before left sidebar.
+    channel_folders.initialize(state_data.channel_folders);
+
     // These components must be initialized early, because other
     // modules' initialization has not been audited for whether they
     // expect DOM elements to always exist (As that did before these

web/tests/channel_folders.test.cjs

@@ -0,0 +1,59 @@
+"use strict";
+
+const assert = require("node:assert/strict");
+
+const {zrequire} = require("./lib/namespace.cjs");
+const {run_test} = require("./lib/test.cjs");
+
+const channel_folders = zrequire("channel_folders");
+
+run_test("basics", () => {
+    const params = {};
+    const frontend_folder = {
+        name: "Frontend",
+        description: "Channels for frontend discussions",
+        rendered_description: "<p>Channels for frontend discussions</p>",
+        creator_id: null,
+        date_created: 1596710000,
+        id: 1,
+        is_archived: false,
+    };
+    const backend_folder = {
+        name: "Backend",
+        description: "Channels for backend discussions",
+        rendered_description: "<p>Channels for backend discussions</p>",
+        creator_id: null,
+        date_created: 1596720000,
+        id: 2,
+        is_archived: false,
+    };
+    params.channel_folders = [frontend_folder, backend_folder];
+    channel_folders.initialize(params);
+
+    assert.deepEqual(channel_folders.get_channel_folders(), [frontend_folder, backend_folder]);
+
+    const devops_folder = {
+        name: "Devops",
+        description: "",
+        rendered_description: "",
+        creator_id: 1,
+        date_created: 1596810000,
+        id: 3,
+        is_archived: false,
+    };
+    channel_folders.add(devops_folder);
+    assert.deepEqual(channel_folders.get_channel_folders(), [
+        frontend_folder,
+        backend_folder,
+        devops_folder,
+    ]);
+
+    devops_folder.is_archived = true;
+    assert.deepEqual(channel_folders.get_channel_folders(), [frontend_folder, backend_folder]);
+
+    assert.deepEqual(channel_folders.get_channel_folders(true), [
+        frontend_folder,
+        backend_folder,
+        devops_folder,
+    ]);
+});