How to call a method from a contract that was instantiated from another contract via truffle console? - ethereum

Question

I'm trying to call a method from a contract that was instantiated from another contract. I use truffle console.
Here are the details: (I think you can gloss over the code, since this question is aimed at using truffle console, not fixing any bugs)
I have a contract called MyCoinSupply.sol:
pragma solidity ^0.8.0;
import "./MyCoin.sol";
contract MyCoinSupply is MyCoin("MyCoin", "MYC") // MyCoin is ERC20
{
constructor() public // gives 1000 tokens to the owner
{
_mint(msg.sender, 1000);
}
function getCoinbase() public returns (address) // for debugging purposes
{
return block.coinbase;
}
function _mintMinerReward() internal // gives 20 tokens to the miner
{
// _mint(block.coinbase, 20); // for some reason, block.coinbase is address 0
}
function _transfer(address from, address to, uint256 value) override internal
{
_mintMinerReward();
super._transfer(from, to, value);
}
}
I instantiate MyCoinSupply.sol within MyCoinDEX.sol:
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./MyCoinSupply.sol";
contract MyCoinDEX
{
IERC20 public token;
event Bought(uint256 amount);
event Sold(uint256 amount);
constructor() public
{
token = new MyCoinSupply();
}
function showSender() public view returns (address) // for debugging purposes
{
return (msg.sender);
}
function buy(uint256 amountTobuy) payable public // send ether and get tokens in exchange; 1 token == 1 ether
{
uint256 dexBalance = token.balanceOf(address(this));
require(amountTobuy > 0, "You need to send some ether");
require(amountTobuy <= dexBalance, "Not enough tokens in the reserve");
token.transfer(msg.sender, amountTobuy);
emit Bought(amountTobuy);
}
function sell(uint256 amount) public // send tokens to get ether back
{
require(amount > 0, "You need to sell at least some tokens");
uint256 allowance = token.allowance(msg.sender, address(this));
require(allowance >= amount, "Check the token allowance");
token.transferFrom(msg.sender, address(this), amount);
payable(msg.sender).transfer(amount);
emit Sold(amount);
}
}
Here's my migration for deploying contracts:
const MyCoinSupply = artifacts.require("MyCoinSupply");
const MyCoinDEX = artifacts.require("MyCoinDEX");
module.exports = function(deployer) {
deployer.deploy(MyCoinSupply);
deployer.deploy(MyCoinDEX);
};
Here's my problem:
When I try to call functions that belong to MyCoinDEX, all works well:
truffle(development)> let instance = await MyCoinDEX.deployed()
undefined
truffle(development)> instance.buy(1)
All is good here.
However, when I try the following I get an error:
truffle(development)> instance.token.balanceOf("0xE1994C1054f9c4171B8ae9a7E7a68F404c2bF829")
evalmachine.<anonymous>:0
instance.token.balanceOf("0xE1994C1054f9c4171B8ae9a7E7a68F404c2bF829")
^
Uncaught TypeError: instance.token.balanceOf is not a function
I Googled this error (I read this solution and this solution), but I didn't really stumble upon a solution. Can someone tell me how can I call token's methods from MyCoinDEX?
Thank you in advance!