Using Node or Typescript

This document provides instructions on how to build with Node.js using the fhevmjs library.

Install the library

First, you need to install the library:

# Using npm
npm install fhevmjs

# Using Yarn
yarn add fhevmjs

# Using pnpm
pnpm add fhevmjs

fhevmjs uses ESM format for web version and commonjs for node version. You need to set the type to "commonjs" in your package.json to load the correct version of fhevmjs. If your node project use "type": "module", you can force the loading of the Node version by using import { createInstance } from 'fhevmjs/node';

Create an instance

An instance receives an object containing:

• chainId (optional): the chainId of the network

• network (optional): the Eip1193 object provided by window.ethereum (used to fetch the public key and/or chain id)

• networkUrl (optional): the URL of the network (used to fetch the public key and/or chain id)

• publicKey (optional): if the public key has been fetched separately (cache), you can provide it

• gatewayUrl (optional): the URL of the gateway to retrieve a reencryption

• coprocessorUrl (optional): the URL of the coprocessor

const { createInstance } = require("fhevmjs");

const createFhevmInstance = async () => {
  return createInstance({
    chainId: 11155111, // Sepolia chain ID
    networkUrl: "https://eth-sepolia.public.blastapi.io", // Sepolia RPC URL
    gatewayUrl: "https://gateway.sepolia.zama.ai",
  });
};
createFhevmInstance().then((instance) => {
  console.log(instance);
});

You can now use your instance to encrypt parameters or do a reencryption.