Set ERC20 token allowance for Smart Wallet Account

Question

I am trying to set USDT(ERC20) token allowance for SWA (smart wallet account) so that the account can interact with an external contract and send USDT to the contract.

I am using Alchemy SDK to create a SWA and ethers.js (v5) to set allowance.

import {
    LightSmartContractAccount,
    getDefaultLightAccountFactoryAddress,
} from "@alchemy/aa-accounts";
import { AlchemyProvider } from "@alchemy/aa-alchemy";
import { LocalAccountSigner, type Hex } from "@alchemy/aa-core";
import { polygon } from "viem/chains";
import { ethers } from "ethers";
import abi from "./erc20.json";

const chain = polygon;

const PRIVATE_KEY = "PRIVATE_KEY_GOES_HERE" as Hex;
const owner = LocalAccountSigner.privateKeyToAccountSigner(PRIVATE_KEY);

// ERC20 token contract details
const erc20Abi = abi; // ERC20 contract ABI
const erc20Address = "0x9999f7Fea5938fD3b1E26A12c3f2fb024e194f97";
const allowanceAmount = ethers.utils.parseUnits("1000", "ether"); // Example allowance

// Create a provider to send user operations from your smart account
const provider = new AlchemyProvider({
// get your Alchemy API key at https://dashboard.alchemy.com
apiKey: "ALCHEMY_API_KEY",
chain,
}).connect(
    (rpcClient) =>
        new LightSmartContractAccount({
        rpcClient,
        owner,
        chain,
        factoryAddress: getDefaultLightAccountFactoryAddress(chain),
        })
);

(async () => {
    const scwAddress = await provider.getAddress()
    console.log("Smart Account Address: ", scwAddress); // Log the smart account address

    // Create an instance of the ERC20 contract
    const rpcUrl = 'https://rpc.ankr.com/polygon';
    const etherProvider = new ethers.providers.JsonRpcProvider(rpcUrl);
    const erc20Contract = new ethers.Contract(erc20Address, erc20Abi, etherProvider);
    
    //Prepare the approve transaction
    const approveTx = await erc20Contract.populateTransaction.approve(scwAddress, allowanceAmount);

    // Retrieve allowance amount below
    const allowance = await erc20Contract.allowance(scwAddress, erc20Address);
    console.log("Allowance: ", allowance.toString());
})();

Perhaps, this error occurs because I have a wrong USDT address or abi.json.

USDT_address = "0x9999f7Fea5938fD3b1E26A12c3f2fb024e194f97";

And here is the abi json that I found in one of public repositories.

[
    {
      "constant": true,
      "inputs": [],
      "name": "name",
      "outputs": [{ "name": "", "type": "string" }],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    },
    {
      "constant": false,
      "inputs": [
        { "name": "_spender", "type": "address" },
        { "name": "_value", "type": "uint256" }
      ],
      "name": "approve",
      "outputs": [{ "name": "", "type": "bool" }],
      "payable": false,
      "stateMutability": "nonpayable",
      "type": "function"
    },
    {
      "constant": true,
      "inputs": [],
      "name": "totalSupply",
      "outputs": [{ "name": "", "type": "uint256" }],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    },
    {
      "constant": false,
      "inputs": [
        { "name": "_from", "type": "address" },
        { "name": "_to", "type": "address" },
        { "name": "_value", "type": "uint256" }
      ],
      "name": "transferFrom",
      "outputs": [{ "name": "", "type": "bool" }],
      "payable": false,
      "stateMutability": "nonpayable",
      "type": "function"
    },
    {
      "constant": true,
      "inputs": [],
      "name": "decimals",
      "outputs": [{ "name": "", "type": "uint8" }],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    },
    {
      "constant": true,
      "inputs": [{ "name": "_owner", "type": "address" }],
      "name": "balanceOf",
      "outputs": [{ "name": "balance", "type": "uint256" }],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    },
    {
      "constant": true,
      "inputs": [],
      "name": "symbol",
      "outputs": [{ "name": "", "type": "string" }],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    },
    {
      "constant": false,
      "inputs": [
        { "name": "_to", "type": "address" },
        { "name": "_value", "type": "uint256" }
      ],
      "name": "transfer",
      "outputs": [{ "name": "", "type": "bool" }],
      "payable": false,
      "stateMutability": "nonpayable",
      "type": "function"
    },
    {
      "constant": true,
      "inputs": [
        { "name": "_owner", "type": "address" },
        { "name": "_spender", "type": "address" }
      ],
      "name": "allowance",
      "outputs": [{ "name": "", "type": "uint256" }],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    },
    { "payable": true, "stateMutability": "payable", "type": "fallback" },
    {
      "anonymous": false,
      "inputs": [
        { "indexed": true, "name": "owner", "type": "address" },
        { "indexed": true, "name": "spender", "type": "address" },
        { "indexed": false, "name": "value", "type": "uint256" }
      ],
      "name": "Approval",
      "type": "event"
    },
    {
      "anonymous": false,
      "inputs": [
        { "indexed": true, "name": "from", "type": "address" },
        { "indexed": true, "name": "to", "type": "address" },
        { "indexed": false, "name": "value", "type": "uint256" }
      ],
      "name": "Transfer",
      "type": "event"
    }
  ]

Answer 1

You can call ERC20 approve function can approve sudt cast limit , allowance is query cureent address approve.

//call auth limit
export const callAuthorizedLimit = async (accountAddress: EthereumAddress, erc20Address: EthereumAddress, amount: bigint, authorizeAddress: EthereumAddress) => {
    const client = await walletClient()
    const { request } = await exportPublicClient.simulateContract({
        account: accountAddress,
        address: erc20Address,
        // @ts-ignore 
        abi: erc20Address.toLocaleLowerCase() === contractAddress.aewTokenAddress.toLocaleLowerCase() ? aewTokenAbi : erc20ABI,
        functionName: "approve",
        args: [authorizeAddress, amount]
    })
    return client?.writeContract(request)
}