Add Modules

Extend the functionality of a FunWallet

Overview

Currently, the FunWallet SDK offers Modules in the following categories:

DeFi

Automatically withdrawal an Aave position

Token Transfer

Transfer tokens

General Flow

The following flow describes a Module's lifecycle. For this example flow, we choose the TokenTransfer Module.

Create Module

Each Module constructor requires a unique set of parameters. For a complete list of Modules and their constructors' parameters, visit the Module Reference section.

import { Modules } from "@fun-wallet/sdk"
const { TokenTransfer } = Modules
const transferModule = new TokenTransfer()

Add Module to FunWallet

A Module can only perform the actions it is intended to once it is connected to a FunWallet. To add a Module to a FunWallet we simply call the addModule method.

await wallet.addModule(transferModule)

Create Required Pre-Execution Transactions

Each Module has a set of Transactions which must be deployed to a blockchain before a Module can be executed on-chain. It is possible for this set to be empty, as is the case for the Token Transfer Module, or consist of many required pre-execution Transactions.

For example, in the case of the EoaAaveWithdrawal Module, there is one pre-execution requirement that needs taking care of, namely giving spend authorization to a FunWallet so it can close an Aave position on behalf of an EOA.

The Module pre-execution required Transactions are obtained by a call to getPreExecTxs. Each Module defines the input arguments to this method. For a complete list of modules and the required pre-execution parameters their constructors take, visit the Module Reference section.

const requiredTransactions = await transferModule.getPreExecTxs(wallet.address)

The returned requiredTransactions element is a set containing Transaction objects to eventually be deployed on a blockchain.

Deploy Required Pre-Execution Transactions

Before we can deploy a Transaction associated with a Module (in the case of TransferToken Module, there is only one possible Transaction: The transfer of a token to another address) we must first deploy all the required pre-execution Transactions obtained from step 3.

const requiredTxReceipts = await wallet.deployTxs(requiredTransactions)

Create Module Execution Transaction

Once we have added a Module to a FunWallet we can get the desired Transaction associated with that Module. In the case of the TransferToken Module, there is only one possible Transaction: The transfer of a token to another address.

const to = "0xB4C3826aFea3Bc437C49695983eAaCFF2Bf8E305" // Receiver of tokens
const amount = ethers.utils.parseEther(".01") // Amount of native gas tokens to transfer
const tokenAddr = "0x9983f755bbd60d1886cbfe103c98c272aa0f03d6" // Address of ERC-20 token to tranfer

const tokenTransferTx = await transferModule.createTransferTx(to, amount, { address: tokenAddr })

Deploy Module Execution Transaction

The last thing left to do once we have deployed the required Module pre-execution Transactions is to deploy the desired Module Transaction itself.

const tokenTransferReceipt = await wallet.deployTx(tokenTransferTx)

Full Example

,add-module.js// 1. Install necessary packages
// npm install @fun-wallet/sdk ethers

// 2. Add Imports
import { ethers } from "ethers"
import { FunWallet, FunWalletConfig, Modules } from "@fun-wallet/sdk"
const { TokenTransfer } = Modules

// 3. Create EOA Instance
// An internal Fun RPC for customer testing
const rpc = "https://avalanche-fuji.infura.io/v3/4a1a0a67f6874be6bb6947a62792dab7"
const provider = new ethers.providers.JsonRpcProvider(rpc)

// Note that the key here will be exposed and should never be used in production
const eoa = new ethers.Wallet(PRIV_KEY, provider)

// To create an EOA instance with an external wallet (e.g MetaMask) do this instead
// const provider = new ethers.providers.Web3Provider(window.ethereum)
// await provider.send('eth_requestAccounts', []) // <- this promps user to connect metamask
// eoa = provider.getSigner()

// 4. Create a FunWallet
const chainID = "43113" // Fuji testnet
const prefundAmt = 0.3 // amount of native gas token to prefund our FunWallet with
const API_KEY = "" // Get your API key from app.fun.xyz/api-key

const config = new FunWalletConfig(eoa, chainID, prefundAmt)
const wallet = new FunWallet(config, API_KEY)
// init will perform the pre-funding of the FunWallet
await wallet.init()

// 5. Create TokenTransfer Module and add it to our FunWallet
const tokenTransferModule = new TokenTransfer()
await wallet.addModule(tokenTransferModule)

// 6. Deploy FunWallet
const deployWalletReceipt = await wallet.deploy()

// 7. Create Required Pre-Execution Transactions
const requiredTransactions = await transferModule.getPreExecTxs(wallet.address)

// 8. Deploy Required Pre-Execution Transactions
const requiredTxReceipts = await wallet.deployTxs(requiredTransactions)

// 9. Create Module Execution Transaction
const to = "0xB4C3826aFea3Bc437C49695983eAaCFF2Bf8E305" // Receiver of tokens
const amount = ethers.utils.parseEther(".01") // Amount of native gas tokens to transfer
const tokenAddr = "0x9983f755bbd60d1886cbfe103c98c272aa0f03d6" // Address of ERC-20 token to tranfer

const tokenTransferTx = await tokenTransferModule.createTransferTx(to, amount, { address: tokenAddr })

// 10. Deploy Module Execution Transaction
const tokenTransferReceipt = await wallet.deployTx(tokenTransferTx)
console.log(tokenTransferReceipt)

,add-module-output.json{
  userOpHash: '0xd7ea68043200a00db7bdf072842cb3669456525ab24db6032f910fe7aafd56cb',
  txid: '0xb98e9c5cd9451a5b7335723f223738eaa0c16b3a60f47e9d3592ff5faef54fb4',
  gasUsed: 173974,
  gasUSD: 0.09142246713
}

To verify that this transaction executed successfully, view the transaction id on your testnet. The example transaction can be found here.

Mentioned Classes

FunWallet

Primary class in the FunWallet SDK that orchestrates the movement of assets & data

FunWalletConfig

FunWallet configuration class

TokenTransfer

Module that enables the transfer of tokens to known addresses