@nomiclabs/hardhat-ethers/src/internal/provider-proxy.ts

Hardhat plugin for ethers

import {
  HARDHAT_NETWORK_RESET_EVENT,
  HARDHAT_NETWORK_REVERT_SNAPSHOT_EVENT,
} from "hardhat/internal/constants";
import { EthereumProvider } from "hardhat/types";

import { EthersProviderWrapper } from "./ethers-provider-wrapper";
import { createUpdatableTargetProxy } from "./updatable-target-proxy";

/**
 * This method returns a proxy that uses an underlying provider for everything.
 *
 * This underlying provider is replaced by a new one after a successful hardhat_reset,
 * because ethers providers can have internal state that returns wrong results after
 * the network is reset.
 */
export function createProviderProxy(
  hardhatProvider: EthereumProvider
): EthersProviderWrapper {
  const initialProvider = new EthersProviderWrapper(hardhatProvider);

  const { proxy: providerProxy, setTarget } =
    createUpdatableTargetProxy(initialProvider);

  hardhatProvider.on(HARDHAT_NETWORK_RESET_EVENT, () => {
    setTarget(new EthersProviderWrapper(hardhatProvider));
  });
  hardhatProvider.on(HARDHAT_NETWORK_REVERT_SNAPSHOT_EVENT, () => {
    setTarget(new EthersProviderWrapper(hardhatProvider));
  });

  return providerProxy;
}