@consensys-software/permissioning-smart-contracts/src/chain/provider.ts

Smart contracts and dapp implementing EEA spec onchain permissioning

import { Provider, AsyncSendable } from 'ethers/providers';
import { ethers, Signer } from 'ethers';
import Web3 from 'web3';

let provider: Provider | Signer | undefined = undefined;
let web3: Web3 | undefined = undefined;
declare let window: any;

const web3Factory = async () => {
  if (web3) return web3;

  if (window.ethereum) {
    await window.ethereum.request({ method: 'eth_requestAccounts' });
  }

  web3 = new Web3(Web3.givenProvider);
  return web3;
};

export const providerFactory = async () => {
  if (provider) return provider;

  const web3 = await web3Factory();
  provider = new ethers.providers.Web3Provider(web3.currentProvider as AsyncSendable).getSigner();

  return provider;
};

export const listenForAccountChange = async (callback: (address: string) => void) => {
  const web3 = await web3Factory();
  let account = (await web3.eth.getAccounts())[0];
  setInterval(async function () {
    const newAccount = (await web3.eth.getAccounts())[0];
    if (newAccount !== account) {
      account = newAccount;
      callback(account);
    }
  }, 100);
};