cometchat-angular-core

Purpose

This is the foundational skill for every CometChat Angular UI Kit v4 integration using the shared uikit-wb-source internally. It teaches Claude HOW CometChat works in Angular — initialization order, UIKitSettingsBuilder pattern, login, environment config, module imports, and the anti-patterns that break real apps.

Supported Angular versions: 12, 13, 14, and 15. Angular 16+ (Signals / standalone-first) is not covered by this skill set.

Read this skill first, before any placement or patterns skill.

Ground truth: docs/ui-kit/angular/getting-started, docs/ui-kit/angular/methods, @cometchat/chat-uikit-angular@4.x exports, @cometchat/uikit-shared exports, @cometchat/uikit-resources exports.

---

1. The init-login-render order

CometChat Angular has exactly one valid lifecycle:

CometChatUIKit.init(UIKitSettings)  →  CometChatUIKit.login({ uid })  →  render <cometchat-*> components

Breaking this order produces a blank component, a "CometChat is not initialized" console error, or a hung login. No exceptions.

UIKitSettingsBuilder — the Angular init pattern

The Angular UI Kit uses UIKitSettingsBuilder from @cometchat/uikit-shared (unlike React Native which uses a flat object). Always use the builder:

import { UIKitSettingsBuilder } from "@cometchat/uikit-shared";
import { CometChatUIKit } from "@cometchat/chat-uikit-angular";
import { environment } from "../environments/environment";

const UIKitSettings = new UIKitSettingsBuilder()
  .setAppId(environment.cometchat.appId)
  .setRegion(environment.cometchat.region)
  .setAuthKey(environment.cometchat.authKey)   // dev only — omit in production
  .subscribePresenceForAllUsers()
  .build();

CometChatUIKit.init(UIKitSettings)
  .then(() => {
    console.log("CometChat initialized");
    // Now safe to call login
  })
  .catch(console.error);

⚠️ UIKitSettingsBuilder is the Angular pattern. Unlike React Native (which uses a flat object), Angular's UI Kit requires the builder chain. Passing a plain object to CometChatUIKit.init() will fail silently or throw a type error.

Init must happen once, before the app bootstraps

The correct place is app.component.ts's ngOnInit or a dedicated AppInitService called from APP_INITIALIZER. Do NOT call init() inside a lazy-loaded module or a component that mounts after routing — by then, components that depend on CometChat may already be rendering.

// app.component.ts
import { Component, OnInit } from "@angular/core";
import { UIKitSettingsBuilder } from "@cometchat/uikit-shared";
import { CometChatUIKit } from "@cometchat/chat-uikit-angular";
import { environment } from "../environments/environment";

@Component({
  selector: "app-root",
  templateUrl: "./app.component.html",
})
export class AppComponent implements OnInit {
  isReady = false;

  ngOnInit(): void {
    const settings = new UIKitSettingsBuilder()
      .setAppId(environment.cometchat.appId)
      .setRegion(environment.cometchat.region)
      .setAuthKey(environment.cometchat.authKey)
      .subscribePresenceForAllUsers()
      .build();

    CometChatUIKit.init(settings)
      .then(() => CometChatUIKit.getLoggedinUser())
      .then((user) => {
        if (!user) {
          return CometChatUIKit.login({ uid: "cometchat-uid-1" });
        }
        return user;
      })
      .then(() => {
        this.isReady = true;
      })
      .catch(console.error);
  }
}

<!-- app.component.html -->
<ng-container *ngIf="isReady">
  <router-outlet></router-outlet>
</ng-container>

Gate the router outlet (or any CometChat component) on isReady. Rendering <cometchat-*> before init + login completes produces blank components.

---

2. Login

Development mode

import { CometChatUIKit } from "@cometchat/chat-uikit-angular";

CometChatUIKit.getLoggedinUser().then((user) => {
  if (!user) {
    CometChatUIKit.login({ uid: "cometchat-uid-1" })
      .then((loggedInUser) => {
        console.log("Login successful:", loggedInUser);
      })
      .catch(console.error);
  }
});

Every new CometChat app ships 5 pre-seeded test users — cometchat-uid-1 through cometchat-uid-5. Use one for development.

⚠️ login() takes an object { uid: "..." }, not a bare string. Passing "cometchat-uid-1" directly throws a type error in TypeScript and silently fails in JavaScript.

Getting the current logged-in user

Two getters exist for different contexts:

// Async — use inside the init/login flow or APP_INITIALIZER
const user = await CometChatUIKit.getLoggedinUser();  // note lowercase 'i' in 'in'
const myUid = user?.getUid();

// Sync — use in guards, components, and anywhere after login completes
import { CometChatUIKitLoginListener } from "@cometchat/chat-uikit-angular";
const user = CometChatUIKitLoginListener.getLoggedInUser();  // note capital 'I' in 'In'
const myUid = user?.getUid();

Default to the sync version in components and route guards — by the time they run, login is already complete. Use the async version only inside the init/login flow itself.

Never hardcode a UID to identify the logged-in user in app logic. Always use one of these getters — in production the UID comes from your auth system, not a test string.

Production mode

Use CometChatUIKit.login({ authToken: "..." }) with a token from your backend. The backend generates the token with the CometChat REST API using the server-only REST API Key. See cometchat-angular-production for the server-side token endpoint patterns.

Logout

CometChatUIKit.logout().then(() => {
  // Navigate to login page
});

---

3. Module setup (mandatory)

Angular requires explicit module imports. Every CometChat component must be imported in the module where it's used.

AppModule setup

// app.module.ts
import { CUSTOM_ELEMENTS_SCHEMA, NgModule } from "@angular/core";
import { BrowserModule } from "@angular/platform-browser";
import { BrowserAnimationsModule } from "@angular/platform-browser/animations";
import {
  CometChatConversationsWithMessages,
  CometChatConversations,
  CometChatMessages,
  CometChatMessageHeader,
  CometChatMessageList,
  CometChatMessageComposer,
  CometChatUsers,
  CometChatGroups,
} from "@cometchat/chat-uikit-angular";
import { AppComponent } from "./app.component";

@NgModule({
  imports: [
    BrowserModule,
    BrowserAnimationsModule,
    // Import only the CometChat components you use
    CometChatConversationsWithMessages,
    CometChatConversations,
    CometChatMessages,
    CometChatMessageHeader,
    CometChatMessageList,
    CometChatMessageComposer,
    CometChatUsers,
    CometChatGroups,
  ],
  declarations: [AppComponent],
  providers: [],
  bootstrap: [AppComponent],
  schemas: [CUSTOM_ELEMENTS_SCHEMA],  // Required for web components
})
export class AppModule {}

⚠️ CUSTOM_ELEMENTS_SCHEMA is required. Without it, Angular throws "Unknown element" errors for every <cometchat-*> tag. Add it to every module that uses CometChat components.

Standalone component setup (Angular 14+)

// chat.component.ts
import { Component } from "@angular/core";
import { CommonModule } from "@angular/common";
import { CometChatConversations } from "@cometchat/chat-uikit-angular";
import { CUSTOM_ELEMENTS_SCHEMA } from "@angular/core";

@Component({
  selector: "app-chat",
  standalone: true,
  imports: [CommonModule, CometChatConversations],
  schemas: [CUSTOM_ELEMENTS_SCHEMA],
  template: `<cometchat-conversations></cometchat-conversations>`,
})
export class ChatComponent {}

---

4. Assets configuration (mandatory)

The Angular UI Kit ships icon assets that must be linked in angular.json. Without this, icons render as broken images.

// angular.json — inside build.options.assets
"assets": [
  "src/favicon.ico",
  "src/assets",
  {
    "glob": "**/*",
    "input": "./node_modules/@cometchat/chat-uikit-angular/assets/",
    "output": "assets/"
  }
]

⚠️ Missing assets config = broken icons throughout the UI Kit. This is the most commonly missed setup step. Always verify angular.json before debugging icon issues.

---

5. Environment variables

Angular does not use .env files or process.env. Configuration lives in src/environments/environment.ts (TypeScript constant objects).

Environment file structure

// src/environments/environment.ts  (development)
export const environment = {
  production: false,
  cometchat: {
    appId: "YOUR_APP_ID",
    region: "us",           // "us" | "eu" | "in"
    authKey: "YOUR_AUTH_KEY",  // dev only — never in production builds
  },
};

// src/environments/environment.prod.ts  (production)
export const environment = {
  production: true,
  cometchat: {
    appId: "YOUR_APP_ID",
    region: "us",
    // No authKey in production — use server-minted auth tokens
    tokenEndpoint: "https://api.yourapp.com/cometchat-token",
  },
};

⚠️ Never put REST_API_KEY in any environment file. Angular bundles environment.ts into the client-side JavaScript. The REST API Key is server-only — it lives in your backend's environment variables, never in the Angular app.

Using environment values

import { environment } from "../environments/environment";

// In your component or service:
const appId = environment.cometchat.appId;

Angular's build system automatically swaps environment.ts for environment.prod.ts when building with --configuration production.

---

6. CometChatThemeService

The Angular UI Kit uses CometChatThemeService (injected via Angular's DI) to control the palette. Inject it in your root component's constructor.

import { Component } from "@angular/core";
import { CometChatThemeService } from "@cometchat/chat-uikit-angular";

@Component({ selector: "app-root", templateUrl: "./app.component.html" })
export class AppComponent {
  constructor(private themeService: CometChatThemeService) {
    // Set mode: "light" | "dark"
    themeService.theme.palette.setMode("light");
    // Set primary brand color
    themeService.theme.palette.setPrimary({ light: "#6851D6", dark: "#6851D6" });
  }
}

CometChatThemeService is a singleton provided at the root level — inject it once in AppComponent and the theme applies globally. See cometchat-angular-theming for the full token reference.

---

7. Package installation

npm install @cometchat/chat-uikit-angular
npm install @cometchat/uikit-elements @cometchat/uikit-resources @cometchat/uikit-shared

The UI Kit depends on @cometchat/chat-sdk-javascript (installed automatically as a peer dep). Do NOT install @cometchat/chat-sdk-javascript separately unless you need a specific version — let the UI Kit manage it.

Peer dependencies

# Required for Angular animations (used by some UI Kit components)
npm install @angular/animations

Ensure BrowserAnimationsModule is imported in AppModule (see § 3).

---

8. Anti-patterns

1. Do NOT call CometChatUIKit.init() inside a lazy-loaded module. Init must complete before any <cometchat-*> component renders. Lazy-loaded modules mount after routing, which is too late.

2. Do NOT use a flat settings object with CometChatUIKit.init(). Angular requires UIKitSettingsBuilder from @cometchat/uikit-shared. The flat-object pattern is React Native only.

3. Do NOT omit CUSTOM_ELEMENTS_SCHEMA from the module. Every module that declares a component using <cometchat-*> tags needs it.

4. Do NOT skip the assets config in angular.json. Icons will be broken without it.

5. Do NOT put authKey in environment.prod.ts. Use server-minted auth tokens in production. See cometchat-angular-production.

6. Do NOT render <cometchat-*> components before isReady. Gate on the init + login promise resolving. Use *ngIf="isReady" on the container.

7. Do NOT call login() with a bare string. It takes { uid: "..." } or { authToken: "..." }.

8. Do NOT import @cometchat/chat-sdk-javascript directly unless you need SDK-level access (e.g., CometChat.getUser(uid)). The UI Kit re-exports the SDK's CometChat namespace — import from @cometchat/chat-sdk-javascript only when you need the raw SDK.

9. Do NOT forget BrowserAnimationsModule in AppModule. Some UI Kit components use Angular animations; missing this module causes runtime errors.

10. Do NOT bundle REST_API_KEY in any Angular file. Angular bundles everything in src/ into the client JavaScript. Server-only keys belong on your backend.

---

9. i18n, RTL, and accessibility

i18n (translations)

The Angular UI Kit ships CometChatLocalize for built-in translations (~40 languages). Initialize it once alongside CometChatUIKit.init():

import { CometChatLocalize } from "@cometchat/chat-uikit-angular";

// In AppComponent.ngOnInit, after init resolves:
CometChatLocalize.init("es"); // "fr", "de", "ar", "hi", etc.

To override specific strings, pass a resources object as the second positional argument:

CometChatLocalize.init("en", {
  en: {
    "type a message": "Write your message…",
  },
});

RTL (right-to-left)

The UI Kit reads dir="rtl" from the document root. Set it in index.html or toggle it dynamically:

<!-- index.html -->
<html dir="rtl" lang="ar">

// Toggle dynamically:
document.documentElement.setAttribute("dir", isRtl ? "rtl" : "ltr");

CometChat components flip automatically — no CometChat-specific config needed.

Accessibility

Default components ship with aria-label on icon-only buttons, role="listbox" on lists, and keyboard navigation (Tab, Enter, Esc). When writing custom ng-template slot views:

1. Icon-only buttons — add aria-label="<verb>" (e.g. aria-label="Send message")
2. Custom list items — keep role="option" + aria-selected on the wrapper
3. Color overrides — verify text contrast ≥ 4.5:1 against background

---

10. Docs MCP (recommended, not required)

The CometChat docs MCP gives runtime access to the most current Angular UI Kit docs. Install:

claude mcp add --transport http cometchat-docs https://www.cometchat.com/docs/mcp

Use the MCP to verify prop names, callback signatures, theme token names, or error message meanings before writing any non-obvious code.

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Skill routing reference

Skill	When to load
cometchat-angular-core	Always — before any integration code
cometchat-angular-components	Always — before writing any <cometchat-*> HTML
cometchat-angular-placement	When integrating — for placement patterns
cometchat-angular-patterns	For Angular-specific routing and module wiring
cometchat-angular-theming	When customizing colors, dark mode, typography
cometchat-angular-features	When adding calls, extensions, AI
cometchat-angular-customization	When customizing components (slot views, formatters, builders)
cometchat-angular-production	When setting up server-side auth + user management
cometchat-angular-troubleshooting	When diagnosing build errors, runtime failures