kyc-signer.ts

import * as sigUtil from 'eth-sig-util';

type CouponType = 'coupon-kyc';
type PrimaryType = 'Message' | 'EIP712Domain';

type CouponData = {
  type: CouponType;
  kycedMember: string;
};

function getMessageDomainType(chainId, verifyingContract, actionId) {
  return {
    name: 'Snapshot Message',
    version: '4',
    chainId,
    verifyingContract,
    actionId,
  };
}

function getDomainType() {
  return [
    {name: 'name', type: 'string'},
    {name: 'version', type: 'string'},
    {name: 'chainId', type: 'uint256'},
    {name: 'verifyingContract', type: 'address'},
    {name: 'actionId', type: 'address'},
  ];
}

function getKycDomainDefinition(verifyingContract, actionId, chainId) {
  const domain = getMessageDomainType(chainId, verifyingContract, actionId);

  const types = {
    Message: [{name: 'kycedMember', type: 'address'}],
    EIP712Domain: getDomainType(),
  };

  return {domain, types};
}

function SigUtilSigner(privateKeyStr) {
  return function (
    m: CouponData,
    verifyingContract: string,
    actionId: string,
    chainId: number
  ) {
    const message: CouponData = m;
    if (privateKeyStr.indexOf('0x') === 0) {
      privateKeyStr = privateKeyStr.slice(2);
    }
    const {domain, types} = getKycDomainDefinition(
      verifyingContract,
      actionId,
      chainId
    );
    return sigUtil.signTypedData_v4(Buffer.from(privateKeyStr, 'hex'), {data: {
      domain,
      message,
      primaryType: 'Message' as PrimaryType,
      types,
    }});
  };
}

function createKycSignature = async ({
    kycOnboardingAdapterAddress,
    daoRegistryAddress,
    memberAddress,
    signerPrivateKey,
  }: CreateCouponSignatureParams): string => {
    try {
      const couponData: CouponData = {
        type: 'coupon-kyc' as CouponType,
        kycedMember: memberAddress,
      };

      const chainId: number = x;// set the ethereum chainId

      // Set the signer private key
      const signature = SigUtilSigner(signerPrivateKey)(
        couponData,
        daoRegistryAddress,
        kycOnboardingAdapterAddress,
        chainId
      );

      return signature;
    } catch (error) {
      console.error(error);

      throw new Error(error.message);
    }
  };