Vertex AI Node.js SDK

The Vertex AI Node.js SDK enables developers to use Google's state-of-the-art generative AI models (like Gemini) to build AI-powered features and applications.

See here for detailed samples using the Vertex AI Node.js SDK.

Before you begin

1. Select or create a Cloud Platform project.
2. Enable billing for your project.
3. Enable the Vertex AI API.
4. Set up authentication with a service account so you can access the API from your local workstation.

Installation

Install this SDK via NPM.

npm install @google-cloud/vertexai

Setup

To use the SDK, create an instance of VertexAI by passing it your Google Cloud project ID and location. Then create a reference to a generative model.

const {VertexAI, HarmCategory, HarmBlockThreshold} = require('@google-cloud/vertexai');

const project = 'your-cloud-project';
const location = 'us-central1';

const vertex_ai = new VertexAI({project: project, location: location});

// Instantiate models
const generativeModel = vertex_ai.preview.getGenerativeModel({
    model: 'gemini-pro',
    // The following parameters are optional
    // They can also be passed to individual content generation requests
    safety_settings: [{category: HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT, threshold: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE}],
    generation_config: {max_output_tokens: 256},
  });

const generativeVisionModel = vertex_ai.preview.getGenerativeModel({
    model: 'gemini-pro-vision',
});

Streaming content generation

async function streamGenerateContent() {
  const request = {
    contents: [{role: 'user', parts: [{text: 'How are you doing today?'}]}],
  };
  const streamingResp = await generativeModel.generateContentStream(request);
  for await (const item of streamingResp.stream) {
    console.log('stream chunk: ', JSON.stringify(item));
  }
  console.log('aggregated response: ', JSON.stringify(await streamingResp.response));
};

streamGenerateContent();

Streaming chat

async function streamChat() {
  const chat = generativeModel.startChat();
  const chatInput1 = "How can I learn more about Node.js?";
  const result1 = await chat.sendMessageStream(chatInput1);
  for await (const item of result1.stream) {
      console.log(item.candidates[0].content.parts[0].text);
  }
  console.log('aggregated response: ', JSON.stringify(await result1.response));
}

streamChat();

Multi-part content generation

Providing a Google Cloud Storage image URI

async function multiPartContent() {
    const filePart = {file_data: {file_uri: "gs://generativeai-downloads/images/scones.jpg", mime_type: "image/jpeg"}};
    const textPart = {text: 'What is this a picture of?'};
    const request = {
        contents: [{role: 'user', parts: [textPart, filePart]}],
      };
    const streamingResp = await generativeVisionModel.generateContentStream(request);
    for await (const item of streamingResp.stream) {
      console.log('stream chunk: ', JSON.stringify(item));
    }
    const aggregatedResponse = await streamingResp.response;
    console.log(aggregatedResponse.candidates[0].content);
}

multiPartContent();

Providing a base64 image string

async function multiPartContentImageString() {
    // Replace this with your own base64 image string
    const base64Image = 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==';
    const filePart = {inline_data: {data: base64Image, mime_type: 'image/jpeg'}};
    const textPart = {text: 'What is this a picture of?'};
    const request = {
        contents: [{role: 'user', parts: [textPart, filePart]}],
      };
    const resp = await generativeVisionModel.generateContentStream(request);
    const contentResponse = await resp.response;
    console.log(contentResponse.candidates[0].content.parts[0].text);
}

multiPartContentImageString();

Multi-part content with text and video

async function multiPartContentVideo() {
    const filePart = {file_data: {file_uri: 'gs://cloud-samples-data/video/animals.mp4', mime_type: 'video/mp4'}};
    const textPart = {text: 'What is in the video?'};
    const request = {
        contents: [{role: 'user', parts: [textPart, filePart]}],
      };
    const streamingResp = await generativeVisionModel.generateContentStream(request);
    for await (const item of streamingResp.stream) {
      console.log('stream chunk: ', JSON.stringify(item));
    }
    const aggregatedResponse = await streamingResp.response;
    console.log(aggregatedResponse.candidates[0].content);
}

multiPartContentVideo();

Content generation: non-streaming

async function generateContent() {
  const request = {
    contents: [{role: 'user', parts: [{text: 'How are you doing today?'}]}],
  };
  const resp = await generativeModel.generateContent(request);

  console.log('aggregated response: ', JSON.stringify(await resp.response));
};

generateContent();

Counting tokens

async function countTokens() {
    const request = {
        contents: [{role: 'user', parts: [{text: 'How are you doing today?'}]}],
      };
    const resp = await generativeModel.countTokens(request);
    console.log('count tokens response: ', resp);
}

countTokens();

License

The contents of this repository are licensed under the Apache License, version 2.0.