index.ts

import type {
  TypedDataDomain,
  TypedDataField,
} from "@ethersproject/abstract-signer";
import { Provider } from "@ethersproject/providers";
import { utils } from "ethers";
import { PublicClient } from "viem";

const VALIDATOR_1271_ABI = [
  "function isValidSignature(bytes32 hash, bytes signature) view returns (bytes4)",
];

// Outputted by solc contracts/DeploylessUniversalSigValidator.sol --bin --optimize --optimize-runs=1
const universalValidator = '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';

type Props = {
  provider?: Provider | PublicClient;
  signer?: string;
  signature: string | Uint8Array;
  message?: string | Uint8Array;
  typedData?: {
    domain: TypedDataDomain;
    types: Record<string, Array<TypedDataField>>;
    message: Record<string, any>;
  };
  finalDigest?: string;
};

/**
 * NOTE: you only need to pass one of: typedData, finalDigest, message
 */
export async function verifyMessage({
  provider,
  signer,
  signature,
  message,
  typedData,
  finalDigest,
}: (
  | Required<Pick<Props, "message">>
  | Required<Pick<Props, "typedData">>
  | Required<Pick<Props, "finalDigest">>
) &
  Props): Promise<boolean> {
  if (message) {
    finalDigest = utils.hashMessage(message);
  } else if (typedData) {
    finalDigest = utils._TypedDataEncoder.hash(
      typedData.domain,
      typedData.types,
      typedData.message
    );
  } else if (!finalDigest) {
    throw Error(
      "Missing one of the properties: message, unPrefixedMessage, typedData or finalDigest"
    );
  }

  // this 'magic' universal validator contract will deploy itself within the eth_call, try to verify the signature using
  // ERC-6492, ERC-1271 and ecrecover, and return the value to us
  const coder = new utils.AbiCoder()
  const callResult = await provider.call({
    data: utils.hexConcat([
      universalValidator,
      coder.encode(['address', 'bytes32', 'bytes'], [signer, finalDigest, signature])
    ]),
  }).then((result : string | { data?: string }) => (typeof result !== 'string') ? result.data : result);

  if (callResult === '0x01') return true
  if (callResult === '0x00') return false
  if (callResult.startsWith('0x08c379a0')) throw new Error(coder.decode(['string'], '0x' + callResult.slice(10))[0])
  throw new Error('Unexpected result from UniversalValidator: '+callResult)
}