getMember.js

import { ethers, BigNumber, utils } from 'ethers'

export const checkSignature = (message, signature) => {
  const msgHash = utils.hashMessage(message)
  const msgHashBytes = utils.arrayify(msgHash)
  const account = utils.recoverAddress(msgHashBytes, signature)
  return account.toLowerCase() || ''
}

export default async function getMember() {
  //Need to add 'Please switch to the approripate network' if not xDai
  const provider = new ethers.providers.Web3Provider(window.ethereum)

  // Prompt user for account connections
  //let result = await provider.send('eth_requestAccounts', [])
  //console.log('The address is ', result[0])

  const signer = provider.getSigner()
  const userAddress = await signer.getAddress()

  const message = 'Sign here.'
  const signature = await signer.signMessage(message)
  const accountFromSignature = checkSignature(message, signature)
  console.log('Account from signature is ', accountFromSignature)

  const contractAddress = '0xD83AC7D30495e1E1d2f42a0D796a058089719a45'
  const abi = [
    {
      type: 'function',
      stateMutability: 'view',
      payable: false,
      outputs: [
        { type: 'address', name: 'delegateKey' },
        { type: 'uint256', name: 'shares' },
        { type: 'uint256', name: 'loot' },
        { type: 'bool', name: 'exists' },
        { type: 'uint256', name: 'highestIndexYesVote' },
        { type: 'uint256', name: 'jailed' },
      ],
      name: 'members',
      inputs: [{ type: 'address', name: '' }],
      constant: true,
    },
  ]
  const contract = new ethers.Contract(contractAddress, abi, provider)
  const memberData = await contract.members(userAddress)
  const existence = memberData.exists
  return existence
}