Build a Validity Transaction

import type { Address, Hex } from 'viem';

const validity = [
  {
    type: 'balance',
    params: {
      address: '0x8ba1f109551bD432803012645Ac136ddd64DBA72' as Address,
      op: '>=',
      value: '0x1' as Hex,
    },
  },
  {
    type: 'storage',
    params: {
      address: '0x8ba1f109551bD432803012645Ac136ddd64DBA72' as Address,
      slot: '0x8' as Hex,
      op: '=',
      value: '0x2a' as Hex,
    },
  },
  {
    type: 'block_number',
    params: { op: '<=', value: '0x11a6a1' as Hex },
  },
] as const;

import { createPublicClient, http, type Chain } from 'viem';
import { privateKeyToAccount } from 'viem/accounts';

const client = createPublicClient({ chain, transport: http(rpcUrl) });
const account = privateKeyToAccount(privateKey);
const fees = await client.estimateFeesPerGas();
const nonce = await client.getTransactionCount({
  address: account.address,
  blockTag: 'latest',
});

const rawTransaction = await account.signTransaction({
  chainId: (chain as Chain).id,
  type: 'eip1559',
  nonce,
  to: '0x...' as Address,
  data: '0x...' as Hex,
  value: 0n,
  gas: 100_000n,
  maxFeePerGas: fees.maxFeePerGas,
  maxPriorityFeePerGas: fees.maxPriorityFeePerGas,
});

const response = await fetch(rpcUrl, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'base_sendRawTransactionValidity',
    params: [rawTransaction, { validity }],
  }),
});

const body = await response.json();
if (body.error) throw new Error(body.error.message);
const hash = body.result;