truffle-multiple-migrations-4.js

2_deploy_contracts.js

const MyERC20 = artifacts.require("MyERC20");
const Exchange = artifacts.require("Exchange");

module.exports = async function(deployer) {
	// deploy MyERC20 and store return value
	let erc20 = await deployer.deploy(MyERC20);
  	// deploy the Exchange and pass erc20
	deployer.deploy(Exchange, erc20);
};