recover

recover.sol

const sigUtil = require('eth-sig-util');
var messageHashx = new Buffer(delegationHash)
const msgParams = { data: messageHashx }
const _signature = sigUtil.personalSign(new Buffer(tokenholder.pk, "hex"),msgParams);

console.log("_signature", _signature);
msgParams.sig = _signature
console.log("recovered address ",sigUtil.recoverPersonalSignature(msgParams));
 
delegatedTransferOperator.methods.recover(delegationHash, _signature).call((error, result) => {
    console.log("_recoverAddress", result);
  });
  

/**
    * @notice Recover signer address from a message by using his signature
    * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
    * @param sig bytes signature, the signature is generated using web3.eth.sign()
    */
  function recover(bytes32 hash, bytes sig) public pure returns (address) {
    bytes32 r;
    bytes32 s;
    uint8 v;

    // Check the signature length
    if (sig.length != 65) {
      return (address(0));
    }

    // Divide the signature in r, s and v variables
    // ecrecover takes the signature parameters, and the only way to get them
    // currently is to use assembly.
    // solium-disable-next-line security/no-inline-assembly
    assembly {
      r := mload(add(sig, 0x20))
      s := mload(add(sig, 0x40))
      v := byte(0, mload(add(sig, 0x60)))
    }

    // Version of signature should be 27 or 28, but 0 and 1 are also possible versions
    if (v < 27) {
      v += 27;
    }

    // If the version is correct return the signer address
    if (v != 27 && v != 28) {
      return (address(0));
    } else {
      return ecrecover(hash, v, r, s);
    }
  }