Generate offchain votes for Snapshot X

generate-vote-msg.js

const { Wallet } = require('@ethersproject/wallet');

const space = '0x1a9fdebf62ed1312354394979c2000d4e7912f9a';
const proposalId = 1;
const choice = 1; // 1: Approve, 2: Reject, 3: Abstain
const chainId = 5; // Goerli

const signer = new Wallet.createRandom(); // Or new Wallet(PRIVATE_KEY);
const voter = signer.address;

const domain = {
  name: 'snapshot-x',
  version: '1.0.0',
  chainId,
  verifyingContract: space
};

const voteTypes = {
  Vote: [
    { name: 'space', type: 'address' },
    { name: 'voter', type: 'address' },
    { name: 'proposalId', type: 'uint256' },
    { name: 'choice', type: 'uint8' }
  ]
};

const message = {
  space,
  voter,
  proposalId,
  choice
};

signer._signTypedData(domain, voteTypes, message).then(sig => {
  console.log('Message', message);
  console.log('Signature', sig);
});