An Ethereum Naming Service contract

[ValentineCodes]

Hey Everyone👋,

Here's an Ethereum Naming Service contract I just wrote. Spot any code smells?

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/// Could not transfer ether
error WithdrawFailed();

contract ENS {

    address public owner;

    string[] names;
    mapping(address => bool) public allAddresses;
    mapping(string => address) public nameToAddress;

    constructor(address _owner) {
        owner = _owner;
    }

    modifier notZeroAddress(address _address) {
        require(_address != address(0), "Zero Addresses are not allowed!");
        _;
    }
    modifier onlyOwner() {
        require(msg.sender == owner, "Only callable by owner!");
        _;
    }

    function changeOwner(address _newOwner) external onlyOwner notZeroAddress(_newOwner) {
        require(msg.sender == owner, "You're not the current owner!");

        owner = _newOwner;
    }

    function add(string calldata _name, address _address) external notZeroAddress(_address) payable {
        require(!allAddresses[_address], "Address already exists!");
        require(nameToAddress[_name] != address(0), "Name already exists!");
        require(msg.value == 1e18, "Insufficient Amount!");
        
        string memory name = string.concat(_name, ".eth");
        
        names.push(name);
        allAddresses[_address] = true;
        nameToAddress[name] = _address;
    }

    function get(string calldata _name) external view returns(address) {
        require(nameToAddress[_name] != address(0),  "Name does not exist!");

        return nameToAddress[_name];
    }

    function validate(string calldata _name) external view returns(bool) {
        if(nameToAddress[_name] != address(0)) return true;
        return false;
    }

    function withdraw() external onlyOwner {
        (bool success,) = payable(owner).call{value: address(this).balance}("");

        if(!success) { revert WithdrawFailed(); }
    }
}

[gmluqa]

Since you're using concat which is a function introduced from solidity 0.8.12, I'd change the pragma to pragma solidity ^0.8.12. Make sure you're using a compiler with 0.8.12 or above!

[ValentineCodes]

Can't believe I missed that. Thanks👌