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The CometChatTextBubble component is a sophisticated message display component that renders text messages with rich formatting capabilities. It serves as the primary content renderer for text-based messages in the CometChat Angular UIKit, handling everything from simple text display to complex features like link previews, translations, mentions, and rich text formatting.

Overview

The Text Bubble component intelligently handles various message types and metadata while maintaining visual consistency with the design system and ensuring full accessibility:
  • Message Object Processing: Extracts text, metadata, and sender information from CometChat.TextMessage objects
  • Rich Text Formatting: Renders rich text HTML with bold, italic, lists, code blocks, and headings
  • Link Previews: Displays rich preview cards for URLs with images, titles, descriptions, and favicons
  • Message Translation: Shows original and translated text side-by-side
  • Mentions Formatting: Highlights @user and @channel mentions with interactive behavior
  • URL Detection: Converts URLs to clickable links
  • Content Truncation: Implements read more/less for long messages
  • Single Emoji Detection: Displays emoji-only messages at larger size
  • Dual Styling: Supports sender (outgoing) and receiver (incoming) visual variants
  • Security: Sanitizes HTML to prevent XSS attacks
  • Accessibility: Full keyboard navigation and screen reader support
Live Preview — Default text bubble preview. Open in Storybook ↗

Basic Usage

Simple Text Message

import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent, MessageBubbleAlignment } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-chat-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="textMessage"
      [alignment]="MessageBubbleAlignment.LEFT"
    ></cometchat-text-bubble>
  `
})
export class ChatMessageComponent {
  textMessage!: CometChat.TextMessage;
  MessageBubbleAlignment = MessageBubbleAlignment;
}

Incoming vs Outgoing Messages

import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent, MessageBubbleAlignment } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-message-list',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <!-- Incoming message (left-aligned) -->
    <cometchat-text-bubble
      [message]="incomingMessage"
      [alignment]="MessageBubbleAlignment.LEFT"
    ></cometchat-text-bubble>

    <!-- Outgoing message (right-aligned) -->
    <cometchat-text-bubble
      [message]="outgoingMessage"
      [alignment]="MessageBubbleAlignment.RIGHT"
    ></cometchat-text-bubble>
  `
})
export class MessageListComponent {
  incomingMessage!: CometChat.TextMessage;
  outgoingMessage!: CometChat.TextMessage;
  MessageBubbleAlignment = MessageBubbleAlignment;
}

With Event Handlers

import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-interactive-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="textMessage"
      (linkClick)="onLinkClick($event)"
      (mentionClick)="onMentionClick($event)"
    ></cometchat-text-bubble>
  `
})
export class InteractiveMessageComponent {
  textMessage!: CometChat.TextMessage;

  onLinkClick(url: string): void {
    console.log('Link clicked:', url);
    // Open URL in new tab or handle custom navigation
    window.open(url, '_blank', 'noopener,noreferrer');
  }

  onMentionClick(user: CometChat.User): void {
    console.log('User mentioned:', user.getName());
    // Navigate to user profile or show user details
  }
}

Properties

PropertyTypeDefaultDescription
messageCometChat.TextMessagerequiredThe CometChat.TextMessage object to render. Contains text content, metadata, and sender information
alignmentMessageBubbleAlignmentMessageBubbleAlignment.LEFTThe alignment of the message bubble. LEFT for incoming/receiver messages, RIGHT for outgoing/sender messages
textFormattersCometChatTextFormatter[][]Array of text formatters to apply to the message text. If empty, default formatters (mentions, URLs) will be used
translatedTextOverridestringundefinedOverride for the translated text display. When provided, this text is shown as the translation instead of the message’s built-in translated text

Events

EventPayload TypeDescription
linkClickstringEmitted when a link preview card or URL link is clicked. Contains the URL string
mentionClickCometChat.UserEmitted when a formatted mention is clicked. Contains the CometChat.User object of the mentioned user

Advanced Usage

The component automatically displays rich link preview cards when message metadata contains link preview data:
import { Component, OnInit } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-link-preview-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="messageWithLinkPreview"
      (linkClick)="onLinkClick($event)"
    ></cometchat-text-bubble>
  `
})
export class LinkPreviewMessageComponent implements OnInit {
  messageWithLinkPreview!: CometChat.TextMessage;

  ngOnInit(): void {
    // Message with link preview metadata structure:
    // metadata: {
    //   "@injected": {
    //     "extensions": {
    //       "link-preview": {
    //         "links": [
    //           {
    //             "url": "https://example.com",
    //             "title": "Example Website",
    //             "description": "This is an example website",
    //             "image": "https://example.com/image.jpg",
    //             "favicon": "https://example.com/favicon.ico"
    //           }
    //         ]
    //       }
    //     }
    //   }
    // }
  }

  onLinkClick(url: string): void {
    window.open(url, '_blank', 'noopener,noreferrer');
  }
}
Link Preview Features:
  • Displays preview image (if available)
  • Shows title and description
  • Extracts and displays domain name
  • Shows favicon (if available)
  • Supports multiple link previews in a single message
  • Clickable cards that emit linkClick event

Messages with Translation

Display original and translated text side-by-side:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-translated-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="translatedMessage"
    ></cometchat-text-bubble>
  `
})
export class TranslatedMessageComponent {
  translatedMessage!: CometChat.TextMessage;

  // Message with translation metadata structure:
  // metadata: {
  //   "translated_message": "This is the translated text"
  // }
}
Translation Display:
  • Shows original text first
  • Visual separator line between original and translated text
  • Localized label “Translated message”
  • Both texts have formatters applied (mentions, URLs, rich text)

Messages with Mentions

The component automatically formats @mentions with interactive behavior:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-mentions-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="messageWithMentions"
      (mentionClick)="onMentionClick($event)"
    ></cometchat-text-bubble>
  `
})
export class MentionsMessageComponent {
  messageWithMentions!: CometChat.TextMessage;

  onMentionClick(user: CometChat.User): void {
    console.log('Mentioned user:', user.getName(), user.getUid());
    // Navigate to user profile or show user card
    this.showUserProfile(user);
  }

  private showUserProfile(user: CometChat.User): void {
    // Implementation for showing user profile
  }
}
Mentions Features:
  • Automatically detects and formats @mentions
  • Different styling for self-mentions vs other users
  • Special styling for @all channel mentions
  • Clickable mentions that emit mentionClick event
  • Accessible with ARIA labels

Messages with Rich Text Formatting

The component renders rich text HTML with bold, italic, lists, code blocks, and more:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-rich-text-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="richTextMessage"
    ></cometchat-text-bubble>
  `
})
export class RichTextMessageComponent {
  richTextMessage!: CometChat.TextMessage;

  // Message text contains rich text HTML:
  // "<p>This is <strong>bold</strong> and <em>italic</em> text</p>"
  // "<ul><li>Item 1</li><li>Item 2</li></ul>"
  // "<pre><code>const x = 1;</code></pre>"
}
Supported Rich Text Elements:
  • Bold (<strong>)
  • Italic (<em>)
  • Underline (<u>)
  • Strikethrough (<s>)
  • Ordered Lists (<ol>, <li>)
  • Unordered Lists (<ul>, <li>)
  • Code Blocks (<pre>, <code>)
  • Headings (<h1> - <h6>)
  • Links (<a>)
Security: All HTML is sanitized to prevent XSS attacks while preserving safe formatting tags.

Long Messages with Read More/Less

The component automatically truncates long messages and provides read more/less controls:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-long-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="longMessage"
    ></cometchat-text-bubble>
  `
})
export class LongMessageComponent {
  longMessage!: CometChat.TextMessage;
  // Message with text exceeding 80px height (approximately 4 lines)
}
Truncation Behavior:
  • Content exceeding 80px height (≈4 lines) is automatically truncated
  • “Read more” button appears for truncated content
  • Clicking “Read more” expands to show full content
  • “Show less” button appears when expanded
  • Clicking “Show less” collapses back to truncated state
  • Buttons use localized text
  • Fully keyboard accessible

Single Emoji Messages

The component detects single emoji messages and displays them at a larger size:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-emoji-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <!-- Single emoji - displays large -->
    <cometchat-text-bubble
      [message]="singleEmojiMessage"
    ></cometchat-text-bubble>

    <!-- Emoji with text - displays normal size -->
    <cometchat-text-bubble
      [message]="emojiWithTextMessage"
    ></cometchat-text-bubble>
  `
})
export class EmojiMessageComponent {
  singleEmojiMessage!: CometChat.TextMessage; // text: "😀"
  emojiWithTextMessage!: CometChat.TextMessage; // text: "😀 Hello"
}
Single Emoji Detection:
  • Detects messages containing exactly one emoji and no other text
  • Handles complex emoji sequences (skin tones, ZWJ sequences, flags)
  • Displays at larger font size for better visibility
  • Whitespace is ignored in detection

Custom Text Formatters

Provide custom text formatters to transform message text:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { 
  CometChatTextBubbleComponent, 
  CometChatTextFormatter,
  CometChatMentionsFormatter,
  CometChatUrlFormatter 
} from '@cometchat/chat-uikit-angular';

// Custom formatter to highlight hashtags
class HashtagFormatter implements CometChatTextFormatter {
  format(text: string): string {
    // Replace #hashtag with styled span
    return text.replace(
      /#(\w+)/g,
      '<span class="hashtag">#$1</span>'
    );
  }

  getKeyboardKey(): string {
    return '#';
  }

  getCharacterLimit(): number {
    return 0; // No limit
  }
}

@Component({
  selector: 'app-custom-formatters',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="textMessage"
      [textFormatters]="customFormatters"
    ></cometchat-text-bubble>
  `,
  styles: [`
    ::ng-deep .hashtag {
      color: #1DA1F2;
      font-weight: 500;
      cursor: pointer;
    }
  `]
})
export class CustomFormattersComponent {
  textMessage!: CometChat.TextMessage;
  
  customFormatters: CometChatTextFormatter[] = [
    new CometChatMentionsFormatter(),
    new CometChatUrlFormatter(),
    new HashtagFormatter()
  ];
}
Formatter Order: Formatters are applied sequentially. Each formatter’s output becomes the input for the next formatter.

Combined Features Example

A message with multiple features working together:
import { Component } from '@angular/core';
import { CometChat } from '@cometchat/chat-sdk-javascript';
import { CometChatTextBubbleComponent } from '@cometchat/chat-uikit-angular';

@Component({
  selector: 'app-complex-message',
  standalone: true,
  imports: [CometChatTextBubbleComponent],
  template: `
    <cometchat-text-bubble
      [message]="complexMessage"
      (linkClick)="onLinkClick($event)"
      (mentionClick)="onMentionClick($event)"
    ></cometchat-text-bubble>
  `
})
export class ComplexMessageComponent {
  complexMessage!: CometChat.TextMessage;

  // Message with:
  // - Rich text formatting (bold, italic)
  // - @mentions
  // - URLs
  // - Link preview metadata
  // - Translation metadata
  // - Long text requiring truncation

  onLinkClick(url: string): void {
    console.log('Link clicked:', url);
  }

  onMentionClick(user: CometChat.User): void {
    console.log('Mention clicked:', user.getName());
  }
}

Customization

Styling with CSS Variables

The Text Bubble component uses CSS variables exclusively for easy customization:
/* Custom text bubble styling */
cometchat-text-bubble {
  /* Spacing */
  --cometchat-spacing-1: 4px;
  --cometchat-spacing-2: 8px;
  --cometchat-spacing-3: 12px;
  --cometchat-spacing-4: 16px;

  /* Typography */
  --cometchat-font-body-regular: 400 14px 'Inter';
  --cometchat-font-body-medium: 500 14px 'Inter';
  --cometchat-font-caption1-regular: 400 12px 'Inter';
  --cometchat-font-title-regular: 400 32px 'Inter';

  /* Colors - Incoming messages */
  --cometchat-background-color-02: #F5F5F5;
  --cometchat-text-color-primary: #141414;
  --cometchat-text-color-secondary: #666666;

  /* Colors - Outgoing messages */
  --cometchat-primary-button-background: #6852D6;
  --cometchat-primary-button-text: #FFFFFF;

  /* Border radius */
  --cometchat-radius-2: 8px;
  --cometchat-radius-3: 12px;

  /* Border colors */
  --cometchat-border-color-light: #E0E0E0;
}

Available CSS Variables

VariablePurposeDefault
--cometchat-spacing-1 to --cometchat-spacing-8Padding, margin, gap4px to 32px
--cometchat-font-body-regularMain text font400 14px Roboto
--cometchat-font-body-mediumMedium weight text500 14px Roboto
--cometchat-font-caption1-regularSmall text (labels)400 12px Roboto
--cometchat-font-title-regularSingle emoji font400 32px Roboto
--cometchat-background-color-02Incoming bubble background#F5F5F5
--cometchat-text-color-primaryPrimary text color#141414
--cometchat-text-color-secondarySecondary text color#666666
--cometchat-primary-button-backgroundOutgoing bubble background#6852D6
--cometchat-primary-button-textOutgoing text color#FFFFFF
--cometchat-radius-2Border radius8px
--cometchat-border-color-lightBorder color#E0E0E0

Custom Color Schemes

/* Blue theme for incoming messages */
.theme-blue cometchat-text-bubble {
  --cometchat-background-color-02: #E3F2FD;
  --cometchat-text-color-primary: #0D47A1;
}

/* Green theme for outgoing messages */
.theme-green cometchat-text-bubble {
  --cometchat-primary-button-background: #4CAF50;
  --cometchat-primary-button-text: #FFFFFF;
}

/* Dark theme */
[data-theme="dark"] cometchat-text-bubble {
  --cometchat-background-color-02: #2C2C2C;
  --cometchat-text-color-primary: #FFFFFF;
  --cometchat-text-color-secondary: #B0B0B0;
  --cometchat-border-color-light: #404040;
}

Custom Mention Styling

/* Custom mention colors */
cometchat-text-bubble {
  /* Self-mention (when you are mentioned) */
  --cometchat-mention-self-background: #FFF3CD;
  --cometchat-mention-self-color: #856404;

  /* Other user mention */
  --cometchat-mention-other-background: #E3F2FD;
  --cometchat-mention-other-color: #1976D2;

  /* Channel mention (@all) */
  --cometchat-mention-channel-background: #FFEBEE;
  --cometchat-mention-channel-color: #C62828;
}

/* Override mention styles directly */
::ng-deep .cometchat-text-bubble__mention--self {
  background-color: #FFF3CD;
  color: #856404;
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 500;
}

::ng-deep .cometchat-text-bubble__mention--other {
  background-color: #E3F2FD;
  color: #1976D2;
  padding: 2px 6px;
  border-radius: 4px;
}

::ng-deep .cometchat-text-bubble__mention--channel {
  background-color: #FFEBEE;
  color: #C62828;
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 600;
}
/* Custom link preview card styling */
::ng-deep .cometchat-text-bubble__link-preview {
  border: 2px solid #E0E0E0;
  border-radius: 12px;
  overflow: hidden;
  transition: transform 0.2s, box-shadow 0.2s;
}

::ng-deep .cometchat-text-bubble__link-preview:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

::ng-deep .cometchat-text-bubble__link-preview-image {
  max-height: 200px;
  object-fit: cover;
}

::ng-deep .cometchat-text-bubble__link-preview-title {
  font-size: 16px;
  font-weight: 600;
  color: #141414;
  margin-bottom: 4px;
}

::ng-deep .cometchat-text-bubble__link-preview-description {
  font-size: 13px;
  color: #666666;
  line-height: 1.4;
}

::ng-deep .cometchat-text-bubble__link-preview-domain {
  font-size: 12px;
  color: #999999;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

Custom Read More/Less Button Styling

/* Custom read more/less button */
::ng-deep .cometchat-text-bubble__read-more-button {
  background: none;
  border: none;
  color: #6852D6;
  font-weight: 600;
  font-size: 13px;
  cursor: pointer;
  padding: 4px 0;
  text-decoration: underline;
  transition: color 0.2s;
}

::ng-deep .cometchat-text-bubble__read-more-button:hover {
  color: #5641B8;
}

::ng-deep .cometchat-text-bubble__read-more-button:focus {
  outline: 2px solid #6852D6;
  outline-offset: 2px;
  border-radius: 2px;
}

Accessibility

The Text Bubble component is fully accessible and follows WCAG 2.1 Level AA guidelines.

WCAG 2.1 Compliance

The component meets the following WCAG 2.1 Level AA success criteria:
  • 1.1.1 Non-text Content (Level A): All images have text alternatives
  • 1.3.1 Info and Relationships (Level A): Proper semantic structure with ARIA roles
  • 2.1.1 Keyboard (Level A): All functionality available via keyboard
  • 2.4.7 Focus Visible (Level AA): Clear focus indicators provided
  • 4.1.2 Name, Role, Value (Level A): All elements have accessible names and roles

Keyboard Support

KeyActionContext
TabNavigate to read more/less buttonWhen button is present
Shift + TabNavigate backwardsWhen button is focused
EnterToggle read more/lessWhen button is focused
SpaceToggle read more/lessWhen button is focused

ARIA Attributes

The component automatically applies appropriate ARIA attributes:
AttributeElementValuePurpose
roleLink preview card"article"Identifies the preview as an article
aria-labelLink preview card"Link preview for {domain}"Provides accessible name
aria-labelRead more button"Read more"Describes button action
aria-labelShow less button"Show less"Describes button action
aria-labelMention element"Mention {username}"Identifies mentioned user
aria-labelURL link"Link opens in new tab"Warns about new tab
targetURL link"_blank"Opens in new tab
relURL link"noopener noreferrer"Security attributes

Screen Reader Behavior

Screen readers announce the text bubble with:
  1. Message text: Read naturally with proper pauses
  2. Mentions: “Mention John Doe” when encountering @mentions
  3. Links: “Link, opens in new tab” for URLs
  4. Link previews: “Article, Link preview for example.com”
  5. Translation: “Translated message” label before translated text
  6. Read more: “Button, Read more” when truncated

Accessibility Best Practices

The component automatically handles all accessibility requirements. No additional ARIA attributes or keyboard handling is needed.
When handling linkClick events, ensure your navigation maintains accessibility by managing focus appropriately.
All interactive elements (read more/less buttons, mentions, links) are keyboard accessible and have visible focus indicators.

Best Practices

Always provide the complete CometChat.TextMessage object to ensure all features (link previews, translations, mentions) work correctly.
The component sanitizes HTML to prevent XSS attacks. Don’t bypass this sanitization or inject unsanitized HTML into the message text.
Use the alignment property to distinguish between incoming and outgoing messages for proper visual styling.
Handle linkClick and mentionClick events to provide interactive behavior like opening URLs or navigating to user profiles.
When providing custom text formatters, ensure they return safe HTML. The component will sanitize the output, but formatters should not introduce XSS vulnerabilities.
The component automatically detects single emoji messages and displays them larger. No special handling is required.
  • CometChatMessageBubble: Uses Text Bubble as the content view for text messages
  • CometChatMessageList: Displays lists of messages including text bubbles
  • CometChatConversations: Shows conversation previews with text message snippets
  • CometChatMessagePreview: Displays message previews in conversation lists

Technical Details

  • Standalone Component: Can be imported and used independently
  • Change Detection: Uses OnPush change detection strategy for optimal performance
  • Dependencies:
    • Angular CommonModule
    • DOMPurify for HTML sanitization
    • CometChat SDK for message types
    • TranslatePipe for localization
  • Bundle Size: Minimal footprint (~8KB including sanitization)
  • BEM CSS: Follows Block Element Modifier naming convention
  • Accessibility: WCAG 2.1 Level AA compliant

Security

XSS Prevention

The component implements comprehensive XSS prevention through HTML sanitization: Sanitization Process:
  1. All HTML content is processed through DOMPurify
  2. Only safe rich text formatting tags are allowed
  3. Script tags, event handlers, and dangerous attributes are stripped
  4. JavaScript URLs (javascript:) and data URIs (data:) are removed
  5. Iframes, objects, and embeds are forbidden
Allowed HTML Tags:
  • Basic formatting: <p>, <br>, <strong>, <em>, <u>, <s>
  • Lists: <ul>, <ol>, <li>
  • Code: <code>, <pre>
  • Headings: <h1> through <h6>
  • Links: <a> (with sanitized href)
Forbidden Elements:
  • <script> tags
  • Event handlers (onclick, onerror, onload, etc.)
  • <iframe>, <object>, <embed> tags
  • <form>, <input> elements
  • <style> tags
  • Data attributes
Never bypass the component’s HTML sanitization. All user-generated content is automatically sanitized to prevent XSS attacks.

Performance Considerations

Optimization Strategies

Change Detection:
  • Uses OnPush strategy to minimize unnecessary re-renders
  • Only updates when inputs change or events are emitted
Content Truncation:
  • Measures content height only once after view initialization
  • Avoids repeated DOM measurements during scrolling
Text Formatting:
  • Formatters are applied sequentially in a single pass
  • Sanitization occurs once after all formatters complete
Link Preview Rendering:
  • Images are lazy-loaded by the browser
  • Failed image loads are handled gracefully without blocking

Best Practices for Performance

Provide text formatters via input to avoid recreating default formatters on every message.
The component uses OnPush change detection. Ensure message objects are immutable for optimal performance.
For troubleshooting tips, see the Troubleshooting Guide.