Nest.js
You can use the AI SDK in a Nest.js server to generate and stream text and objects to the client.
Examples
The examples show how to implement a Nest.js controller that uses the AI SDK to stream text and objects to the client.
Full example: github.com/vercel/ai/examples/nest
Data Stream
You can use the pipeDataStreamToResponse
method to get a data stream from the result and then pipe it to the response.
app.controller.ts
import { Controller, Post, Res } from '@nestjs/common';import { openai } from '@ai-sdk/openai';import { streamText } from 'ai';import { Response } from 'express';
@Controller()export class AppController { @Post() async example(@Res() res: Response) { const result = streamText({ model: openai('gpt-4o'), prompt: 'Invent a new holiday and describe its traditions.', });
result.pipeDataStreamToResponse(res); }}
Sending Custom Data
createDataStream
can be used to send custom data to the client.
app.controller.ts
import { Controller, Post, Res } from '@nestjs/common';import { openai } from '@ai-sdk/openai';import { createDataStream, streamText } from 'ai';import { Response } from 'express';
@Controller()export class AppController { @Post('/stream-data') async streamData(@Res() res: Response) { pipeDataStreamToResponse(res, { execute: async dataStreamWriter => { dataStreamWriter.writeData('initialized call');
const result = streamText({ model: openai('gpt-4o'), prompt: 'Invent a new holiday and describe its traditions.', });
result.mergeIntoDataStream(dataStreamWriter); }, onError: error => { // Error messages are masked by default for security reasons. // If you want to expose the error message to the client, you can do so here: return error instanceof Error ? error.message : String(error); }, }); }}
Text Stream
You can use the pipeTextStreamToResponse
method to get a text stream from the result and then pipe it to the response.
app.controller.ts
import { Controller, Post, Res } from '@nestjs/common';import { openai } from '@ai-sdk/openai';import { streamText } from 'ai';import { Response } from 'express';
@Controller()export class AppController { @Post() async example(@Res() res: Response) { const result = streamText({ model: openai('gpt-4o'), prompt: 'Invent a new holiday and describe its traditions.', });
result.pipeTextStreamToResponse(res); }}