hardhat.config.js

require('@nomiclabs/hardhat-waffle');
require('dotenv').config();

// This is a sample Hardhat task. To learn how to create your own go to
// https://hardhat.org/guides/create-task.html
task('accounts', 'Prints the list of accounts', async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners();

  for (const account of accounts) {
    console.log(account.address);
  }
});

function mnemonic() {
  //can config 3 PRIVATE_KEY
  //return process.env.PRIVATE_KEY,process.env.PRIVATE_KEY1,process.env.PRIVATE_KEY2;
  return process.env.PRIVATE_KEY;
}

// You need to export an object to set up your config
// Go to https://hardhat.org/config/ to learn more

/**
 * @type import('hardhat/config').HardhatUserConfig
 */
module.exports = {
  networks: {
    hardhat: {},
    sepolia: {
      url: `https://sepolia.infura.io/v3/${process.env.INFURA_ID}`,
      accounts: [mnemonic()],
    },
    mainnet: {
      url: `https://mainnet.infura.io/v3/${process.env.INFURA_ID}`,
      accounts: [mnemonic()],
    },
  },
  solidity: '0.8.4',
  mocha: {
    timeout: 60000,
  },
};