hardhat_impersonate.ts

// ethers.js v5

import { ethers, network } from "hardhat";
import { SignerWithAddress } from "@nomiclabs/hardhat-ethers/signers";

async function impersonate(
    who: string,
    f: (signer: SignerWithAddress) => Promise<void>
): Promise<void> {
    await network.provider.request({
        method: "hardhat_impersonateAccount",
        params: [who],
    });
    const signer = await ethers.getSigner(who);
    try {
        await f(signer);
    } finally {
        network.provider.request({
            method: "hardhat_stopImpersonatingAccount",
            params: [who],
        });
    }
}

// JavaScript

const { ethers, network } = require('hardhat');

async function impersonate(who, f) {
  await network.provider.request({
    method: 'hardhat_impersonateAccount',
    params: [who],
  });
  const signer = await ethers.getSigner(who);
  try {
    await f(signer);
  } finally {
    network.provider.request({
      method: 'hardhat_stopImpersonatingAccount',
      params: [who],
    });
  }
}