Example Multicall

multicall.ts

import {
  createPublicClient,
  decodeFunctionResult,
  encodeFunctionData,
  http,
  parseAbi,
} from "viem";
import { mainnet } from "viem/chains";

const multicallAbi = [
  {
    type: 'function',
    name: 'aggregate',
    inputs: [
      {
        name: 'calls',
        type: 'tuple[]',
        components: [
          { name: 'target', type: 'address' },
          { name: 'callData', type: 'bytes' },
        ],
      },
    ],
    outputs: [
      { name: 'blockNumber', type: 'uint256' },
      { name: 'returnData', type: 'bytes[]' },
    ],
    stateMutability: 'view',
  },
] as const;

const run = async (): Promise<void> => {
  const client = createPublicClient({
    chain: mainnet,
    transport: http(),
  });

  const MULTICALL_ADDRESS = "0x5ba1e12693dc8f9c48aad8770482f4739beed696"; // Mainnet Multicall v2

  const calls = [
    {
      target: "0x6b175474e89094c44da98b954eedeac495271d0f" as `0x${string}`, // DAI contract
      callData: encodeFunctionData({
        abi: parseAbi(["function totalSupply() view returns (uint256)"]),
        functionName: "totalSupply",
      }),
    },
    {
      target: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" as `0x${string}`, // USDC contract
      callData: encodeFunctionData({
        abi: parseAbi(["function name() view returns (string)"]),
        functionName: "name",
      }),
    },
  ] as const;

  const result = await client.readContract({
    address: MULTICALL_ADDRESS,
    abi: multicallAbi,
    functionName: "aggregate",
    args: [calls],
  });
  console.log(result);
  const [, returnData] = result;

  const daiTotalSupply = decodeFunctionResult({
    abi: parseAbi(["function totalSupply() view returns (uint256)"]),
    functionName: "totalSupply",
    data: returnData[0],
  });

  const usdcName = decodeFunctionResult({
    abi: parseAbi(["function name() view returns (string)"]),
    functionName: "name",
    data: returnData[1],
  });

  console.log({ daiTotalSupply, usdcName });
};

run();