How to extract the custom reverted message inside the transaction object when we're using solidity error keyword?

Question

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.4;

error Unauthorized();

contract VendingMachine {
    address payable owner = payable(msg.sender);

    function withdraw() public {
        if (msg.sender != owner)
            revert Unauthorized();

        owner.transfer(address(this).balance);
    }
    // ...
}

How can I extract Unauthorized when the transaction reverts by using ethersjs?

Answer 1

You can find a good answer in an article here: https://soliditylang.org/blog/2021/04/21/custom-errors/ and here: https://stackoverflow.com/questions/76550726/how-to-extract-error-message-from-transaction-using-ethers-js