@langchain/openai

This package contains the LangChain.js integrations for OpenAI through their SDK.

Installation

npm install @langchain/openai @langchain/core
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This package, along with the main LangChain package, depends on @langchain/core. If you are using this package with other LangChain packages, you should make sure that all of the packages depend on the same instance of @langchain/core. You can do so by adding appropriate fields to your project's package.json like this:

{
  "name": "your-project",
  "version": "0.0.0",
  "dependencies": {
    "@langchain/core": "^0.3.0",
    "@langchain/openai": "^0.0.0"
  },
  "resolutions": {
    "@langchain/core": "^0.3.0"
  },
  "overrides": {
    "@langchain/core": "^0.3.0"
  },
  "pnpm": {
    "overrides": {
      "@langchain/core": "^0.3.0"
    }
  }
}
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The field you need depends on the package manager you're using, but we recommend adding a field for the common pnpm, npm, and yarn to maximize compatibility.

Chat Models

This package contains the ChatOpenAI class, which is the recommended way to interface with the OpenAI series of models.

To use, install the requirements, and configure your environment.

export OPENAI_API_KEY=your-api-key
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Then initialize

import { ChatOpenAI } from "@langchain/openai";

const model = new ChatOpenAI({
  apiKey: process.env.OPENAI_API_KEY,
  model: "gpt-4-1106-preview",
});
const response = await model.invoke(new HumanMessage("Hello world!"));
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Streaming

import { ChatOpenAI } from "@langchain/openai";

const model = new ChatOpenAI({
  apiKey: process.env.OPENAI_API_KEY,
  model: "gpt-4-1106-preview",
});
const response = await model.stream(new HumanMessage("Hello world!"));
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Embeddings

This package also adds support for OpenAI's embeddings model.

import { OpenAIEmbeddings } from "@langchain/openai";

const embeddings = new OpenAIEmbeddings({
  apiKey: process.env.OPENAI_API_KEY,
});
const res = await embeddings.embedQuery("Hello world");
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Development

To develop the OpenAI package, you'll need to follow these instructions:

Install dependencies

pnpm install
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Build the package

pnpm build
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Or from the repo root:

pnpm build --filter=@langchain/openai
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Run tests

Test files should live within a tests/ file in the src/ folder. Unit tests should end in .test.ts and integration tests should end in .int.test.ts:

$ pnpm test
$ pnpm test:int
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Lint & Format

Run the linter & formatter to ensure your code is up to standard:

pnpm lint && pnpm format
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Adding new entrypoints

If you add a new file to be exported, either import & re-export from src/index.ts, or add it to the exports field in the package.json file and run pnpm build to generate the new entrypoint.