Backend API
<div class="demo-container">
<dx-chat
[class.chat-disabled]="isDisabled"
[dataSource]="dataSource"
[reloadOnChange]="false"
[showAvatar]="false"
[showDayHeaders]="false"
[user]="user"
height="710"
[typingUsers]="typingUsers$ | async"
[alerts]="alerts$ | async"
(onMessageEntered)="onMessageEntered($event)"
messageTemplate="messageTemplate"
[speechToTextEnabled]="true"
>
<div *dxTemplate="let data of 'messageTemplate'">
@if (data.message.text === regenerationText) {
<ng-container>
<span>{{ regenerationText }}</span>
</ng-container>
} @if (data.message.text !== regenerationText) {
<ng-container>
<div
class="chat-messagebubble-text"
[innerHTML]="convertToHtml(data.message)"
>
</div>
<div class="bubble-button-container">
<dx-button
[icon]="copyButtonIcon"
stylingMode="text"
hint="Copy"
(onClick)="onCopyButtonClick(data.message)"
>
</dx-button>
<dx-button
icon="refresh"
stylingMode="text"
hint="Regenerate"
(onClick)="onRegenerateButtonClick()"
>
</dx-button>
</div>
</ng-container>
}
</div>
</dx-chat>
</div>
import { bootstrapApplication } from '@angular/platform-browser';
import {
ChangeDetectorRef, Component, enableProdMode, provideZoneChangeDetection,
} from '@angular/core';
import { AsyncPipe } from '@angular/common';
import { DxChatModule, DxButtonModule } from 'devextreme-angular';
import type { DxChatTypes } from 'devextreme-angular/ui/chat';
import { Observable } from 'rxjs';
import { loadMessages } from 'devextreme-angular/common/core/localization';
import { DataSource } from 'devextreme-angular/common/data';
import { AppService } from './app.service';
import { AiService } from './ai/ai.service';
if (!/localhost/.test(document.location.host)) {
enableProdMode();
}
@Component({
selector: 'demo-app',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css'],
imports: [
DxChatModule,
DxButtonModule,
AsyncPipe,
],
})
export class AppComponent {
dataSource: DataSource;
user: DxChatTypes.User;
typingUsers$: Observable<DxChatTypes.User[]>;
alerts$: Observable<DxChatTypes.Alert[]>;
regenerationText: string;
copyButtonIcon: string;
isDisabled: boolean;
constructor(
private readonly appService: AppService,
private readonly changeDetectorRef: ChangeDetectorRef,
) {
loadMessages(this.appService.getDictionary());
this.dataSource = this.appService.dataSource;
this.user = this.appService.user;
this.alerts$ = this.appService.alerts$;
this.typingUsers$ = this.appService.typingUsers$;
this.regenerationText = this.appService.REGENERATION_TEXT;
this.copyButtonIcon = 'copy';
this.isDisabled = false;
}
convertToHtml(message: DxChatTypes.Message): string {
return this.appService.convertToHtml(message.text);
}
toggleDisabledState(disabled: boolean, event = undefined) {
this.isDisabled = disabled;
if (disabled) {
event?.target.blur();
} else {
event?.target.focus();
}
this.changeDetectorRef.detectChanges();
}
async onMessageEntered(e: DxChatTypes.MessageEnteredEvent) {
if (!this.appService.alerts.length) {
this.toggleDisabledState(true, e.event);
}
try {
await this.appService.onMessageEntered(e);
} finally {
this.toggleDisabledState(false, e.event);
}
}
onCopyButtonClick(message: DxChatTypes.Message) {
navigator.clipboard?.writeText(message.text);
this.copyButtonIcon = 'check';
setTimeout(() => {
this.copyButtonIcon = 'copy';
this.changeDetectorRef.detectChanges();
}, 2500);
}
async onRegenerateButtonClick() {
this.appService.updateLastMessage();
this.toggleDisabledState(true);
try {
await this.appService.regenerate();
} finally {
this.toggleDisabledState(false);
}
}
}
bootstrapApplication(AppComponent, {
providers: [
provideZoneChangeDetection({ eventCoalescing: true, runCoalescing: true }),
AppService,
AiService,
],
});
.demo-container {
display: flex;
justify-content: center;
}
::ng-deep .dx-chat {
max-width: 900px;
}
::ng-deep .dx-chat-messagelist-empty-image {
display: none;
}
::ng-deep .dx-chat-messagelist-empty-message {
font-size: var(--dx-font-size-heading-5);
}
::ng-deep .dx-chat-messagebubble-content,
::ng-deep .chat-messagebubble-text {
display: flex;
flex-direction: column;
}
::ng-deep .bubble-button-container {
display: none;
}
::ng-deep .dx-button {
display: inline-block;
color: var(--dx-color-icon);
}
::ng-deep .dx-chat-messagegroup-alignment-start:last-child .dx-chat-messagebubble:last-child .bubble-button-container {
display: flex;
gap: 4px;
margin-top: 8px;
}
::ng-deep .dx-template-wrapper > div > p:first-child {
margin-top: 0;
}
::ng-deep .dx-template-wrapper > div > p:last-child {
margin-bottom: 0;
}
::ng-deep .dx-chat-messagebubble-content h1,
::ng-deep .dx-chat-messagebubble-content h2,
::ng-deep .dx-chat-messagebubble-content h3,
::ng-deep .dx-chat-messagebubble-content h4,
::ng-deep .dx-chat-messagebubble-content h5,
::ng-deep .dx-chat-messagebubble-content h6 {
font-size: revert;
font-weight: revert;
}
::ng-deep .chat-disabled .dx-chat-messagebox {
opacity: 0.5;
pointer-events: none;
}
import { Injectable } from '@angular/core';
import { Observable, BehaviorSubject } from 'rxjs';
import { unified } from 'unified';
import remarkParse from 'remark-parse';
import remarkRehype from 'remark-rehype';
import rehypeStringify from 'rehype-stringify';
import rehypeMinifyWhitespace from 'rehype-minify-whitespace';
import { type DxChatTypes } from 'devextreme-angular/ui/chat';
import { DataSource, CustomStore } from 'devextreme-angular/common/data';
import { AiService, type AIMessage } from './ai/ai.service';
@Injectable({
providedIn: 'root',
})
export class AppService {
aiService: AiService;
REGENERATION_TEXT = 'Regeneration...';
ALERT_TIMEOUT = 1000 * 60;
user: DxChatTypes.User = {
id: 'user',
};
assistant: DxChatTypes.User = {
id: 'assistant',
name: 'Virtual Assistant',
};
store: any[] = [];
messages: AIMessage[] = [];
alerts: DxChatTypes.Alert[] = [];
customStore: CustomStore;
dataSource: DataSource;
typingUsersSubject: BehaviorSubject<DxChatTypes.User[]> = new BehaviorSubject([]);
alertsSubject: BehaviorSubject<DxChatTypes.Alert[]> = new BehaviorSubject([]);
constructor(aiService: AiService) {
this.aiService = aiService;
this.initDataSource();
this.typingUsersSubject.next([]);
this.alertsSubject.next([]);
}
get typingUsers$(): Observable<DxChatTypes.User[]> {
return this.typingUsersSubject.asObservable();
}
get alerts$(): Observable<DxChatTypes.Alert[]> {
return this.alertsSubject.asObservable();
}
getDictionary() {
return {
en: {
'dxChat-emptyListMessage': 'Chat is Empty',
'dxChat-emptyListPrompt': 'AI Assistant is ready to answer your questions.',
'dxChat-textareaPlaceholder': 'Ask AI Assistant...',
},
};
}
initDataSource() {
this.customStore = new CustomStore({
key: 'id',
load: () => new Promise((resolve) => {
setTimeout(() => {
resolve([...this.store]);
}, 0);
}),
insert: (message) => new Promise((resolve) => {
setTimeout(() => {
this.store.push(message);
resolve(message);
});
}),
});
this.dataSource = new DataSource({
store: this.customStore,
paginate: false,
});
}
getAIResponse(messages: AIMessage[]): Promise<string> {
return this.aiService.getAIResponse(messages) as Promise<string>;
}
async processMessageSending(message: DxChatTypes.Message) {
this.messages.push({ role: 'user', content: message.text });
this.typingUsersSubject.next([this.assistant]);
try {
const aiResponse = await this.getAIResponse(this.messages);
setTimeout(() => {
this.typingUsersSubject.next([]);
this.messages.push({ role: 'assistant', content: aiResponse });
this.renderAssistantMessage(aiResponse);
}, 200);
} catch {
this.typingUsersSubject.next([]);
this.messages.pop();
this.alertLimitReached();
}
}
updateLastMessage(text = this.REGENERATION_TEXT) {
const items = this.dataSource.items();
const lastMessage = items.at(-1);
this.dataSource.store().push([{
type: 'update',
key: lastMessage.id,
data: { text },
}]);
}
renderAssistantMessage(text: string) {
const message = {
id: Date.now(),
timestamp: new Date(),
author: this.assistant,
text,
};
this.dataSource.store().push([{ type: 'insert', data: message }]);
}
alertLimitReached() {
this.setAlerts([{
message: 'Request limit reached, try again in a minute.',
}]);
setTimeout(() => {
this.setAlerts([]);
}, this.ALERT_TIMEOUT);
}
setAlerts(alerts: DxChatTypes.Alert[]) {
this.alerts = alerts;
this.alertsSubject.next(alerts);
}
async regenerate() {
try {
const aiResponse = await this.getAIResponse(this.messages.slice(0, -1));
this.updateLastMessage(aiResponse);
this.messages.at(-1).content = aiResponse;
} catch {
this.updateLastMessage(this.messages.at(-1).content);
this.alertLimitReached();
}
}
convertToHtml(value: string) {
const result = unified()
.use(remarkParse)
.use(remarkRehype)
.use(rehypeMinifyWhitespace)
.use(rehypeStringify)
.processSync(value)
.toString();
return result;
}
async onMessageEntered({ message, event }: DxChatTypes.MessageEnteredEvent) {
this.dataSource.store().push([{ type: 'insert', data: { id: Date.now(), ...message } }]);
if (!this.alerts.length) {
await this.processMessageSending(message, event);
}
}
}
<!DOCTYPE html>
<html lang="en">
<head>
<title>DevExtreme Demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/26.1.5/css/dx.light.css" />
</head>
<body class="dx-viewport">
<div class="demo-container">
<demo-app>Loading...</demo-app>
</div>
<script src="https://cdn.jsdelivr.net/npm/zone.js@0.16.2/bundles/zone.umd.js"></script>
<script src="./bundle.js" type="module"></script>
</body>
</html>
import { Injectable } from '@angular/core';
import { AzureOpenAI, OpenAI } from 'openai';
import { type AIResponse } from 'devextreme-angular/common/ai-integration';
export type AIMessage = (
OpenAI.ChatCompletionUserMessageParam
| OpenAI.ChatCompletionSystemMessageParam
| OpenAI.ChatCompletionAssistantMessageParam) & {
content: string;
};
const AzureOpenAIConfig = {
dangerouslyAllowBrowser: true,
deployment: 'demo-mini',
apiVersion: '2024-02-01',
endpoint: 'https://public-api.devexpress.com/demo-openai',
apiKey: 'DEMO',
};
@Injectable()
export class AiService {
chatService: AzureOpenAI;
constructor() {
this.chatService = new AzureOpenAI(AzureOpenAIConfig);
}
async getAIResponse(messages: AIMessage[]): Promise<AIResponse> {
const params = {
messages,
model: AzureOpenAIConfig.deployment,
max_completion_tokens: 1000,
temperature: 0.7,
};
const response = await this.chatService.chat.completions.create(params);
const data = { choices: response.choices };
return data.choices[0].message?.content;
}
}
Custom Message Template
The Chat specifies a messageTemplate that displays "Copy" and "Regenerate" buttons in bot messages.
Response Format Conversion: Markdown to HTML
The AI model outputs responses in Markdown, while the Chat requires HTML output. This example uses the unified plugin library to convert response content. Review convertToHtml function code for implementation details.
Default Caption Customization
The Chat component in this demo displays modified captions when the conversation is empty. The demo uses localization techniques to alter built-in text.
Speech Recognition
Users can enter voice-driven messages when speechToTextEnabled is set to true. Our Chat component uses Web Speech APIs for speech recognition. Use speechToTextOptions to define custom speech recognizer settings, handle related events, and customize the speech-to-text button appearance.