request({ 
  method: "eth_signTypedData_v4",
  params: [address, JSON.stringify(typedDataObject)]
})

import { LocalAccountSigner } from "@aa-sdk/core";
import { createLightAccountAlchemyClient } from "@account-kit/smart-contracts";
import { alchemy, arbitrumSepolia } from "@account-kit/infra";

const { PRIVATE_KEY, ALCHEMY_API_KEY, ALCHEMY_POLICY_ID } = process.env;

const client = await createLightAccountAlchemyClient({
  transport: alchemy({ apiKey: ALCHEMY_API_KEY }),
  chain: arbitrumSepolia,
  signer: LocalAccountSigner.privateKeyToAccountSigner(PRIVATE_KEY),
  policyId: ALCHEMY_POLICY_ID,
});
console.log("client.account.address", client.account.address);

const typedData = {
  domain: {
    chainId: arbitrumSepolia.id,
    name: "Ether Mail",
    verifyingContract: "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
    version: "1",
  },
  message: {
    contents: "Hello, Bob!",
    from: {
      name: "Cow",
      wallets: [
        "0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826",
        "0xDeaDbeefdEAdbeefdEadbEEFdeadbeEFdEaDbeeF",
      ],
    },
    to: [
      {
        name: "Bob",
        wallets: [
          "0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB",
          "0xB0BdaBea57B0BDABeA57b0bdABEA57b0BDabEa57",
          "0xB0B0b0b0b0b0B000000000000000000000000000",
        ],
      },
    ],
  },
  primaryType: "Mail",
  types: {
    EIP712Domain: [
      { name: "name", type: "string" },
      { name: "version", type: "string" },
      { name: "chainId", type: "uint256" },
      { name: "verifyingContract", type: "address" },
    ],
    Mail: [
      { name: "from", type: "Person" },
      { name: "to", type: "Person[]" },
      { name: "contents", type: "string" },
    ],
    Person: [
      { name: "name", type: "string" },
      { name: "wallets", type: "address[]" },
    ],
  },
};

// this will throw
const sign = await client.request({
  method: "eth_signTypedData_v4",
  params: [client.account.address, JSON.stringify(typedData)],
});

console.log("sign", sign);