Is possible to see output data when tracking a transaction from its address on Etherscan?

Question

I wonder if it is possible to see "Output Data" on Etherscan for non-view transactions that returned values, I mean it is possible to see "Input Data" when fetching a transaction on Etherscan from its address but can I find transaction's output data?

Answer 1

Not possible by design. Returned values from functions invoked by a transaction are not available outside of EVM message calls (aka internal transactions).

You can either emit an event or create a getter function to retrieve the value.

pragma solidity ^0.8;

contract MyContract {
    uint256 number;
    event NumberChanged(uint256);

    function setNumber(uint256 _number) public returns (uint256) {
        number = _number;

        // available outside of EVM, n/a for internal transactions
        emit NumberChanged(_number);

        // available for internal transactions inside EVM, n/a outside
        return _number;
    }

    // available for both internal transactions and outside of EVM
    function getNumber() public view returns (uint256) {
        return number;
    }
}