With TypeScript

LlamaIndex.TS is written in TypeScript and designed to be used in TypeScript projects.

We put a lot of work on strong typing to make sure you have a great typing experience with code completion such as:

import { PromptTemplate } from 'llamaindex'
const promptTemplate = new PromptTemplate({
  template: `Context information from multiple sources is below.
---------------------
{context}
---------------------
Given the information from multiple sources and not prior knowledge.
Answer the query in the style of a Shakespeare play"
Query: {query}
Answer:`,
	templateVars: ["context", "query"],
});
promptTemplate.format({
	ccontext
})

Enable TypeScript

Make sure to set moduleResolution in your tsconfig.json file:

{
  compilerOptions: {
    // ⬇️ add this line to your tsconfig.json
    moduleResolution: "bundler", // or "nodenext" | "node16" | "node"
  },
}

We recommend using bundler or nodenext, but due to popularity of node, we still added support for it, but with import path limitations.

So you may encounter type errors when importing sub paths from the llamaindex package like:

import { Settings } from "llamaindex";

The simplest way to fix this without changing moduleResolution is to import directly from llamaindex:

import { Settings } from "llamaindex";

Enable AsyncIterable for `Web Stream` API

Some modules uses Web Stream API like ReadableStream and WritableStream, you need to enable DOM.AsyncIterable in your tsconfig.json.

{
  compilerOptions: {
    // ⬇️ add this lib to your tsconfig.json
    lib: ["DOM.AsyncIterable"],
  },
}

import { agent, tool } from 'llamaindex'
import { openai } from "@llamaindex/openai";
 
Settings.llm = openai({
  model: "gpt-4o-mini",
});
 
const addTool = tool({
  name: "add", 
  description: "Adds two numbers",
  parameters: z.object({x: z.number(), y: z.number()}),
  execute: ({ x, y }) => x + y,
});
 
const myAgent = agent({
  tools: [addTool],
});
 
// Chat with the agent
const context = myAgent.run("Hello, how are you?");
 
for await (const event of context) {
  if (event instanceof AgentStream) {
    for (const chunk of event.data.delta) {
      process.stdout.write(chunk); // stream response
    }
  } else {
    console.log(event); // other events
  }
}

Run TypeScript Script in Node.js

We recommend to use tsx to run TypeScript script in Node.js.

node --import tsx ./my-script.ts

With TypeScript

Enable TypeScript

Enable AsyncIterable for Web Stream API

Run TypeScript Script in Node.js

On this page

Enable AsyncIterable for `Web Stream` API