Simple Token

Create contract with name UTSTokenShowcase .

You need to import:

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@entangle-labs/uts-contracts/contracts/ERC20/UTSBase";

We are starting with defining contract and dependencies. As access control we are choosing Ownable and also since it is UTS Token we need to import ERC20 implementation, here we are using one by OpenZeppelin.

UTSBase is our main contract that should be inherited by any Token or Connector.

In this implementation we also used Ownable and ERC20

contract UTSTokenShowcase is UTSBase, Ownable, ERC20 {}

constructor(
    address _router,  
    uint256[] memory _allowedChainIds,
    ChainConfig[] memory _chainConfigs
) Ownable(msg.sender) ERC20("UTS Token Showcase", "UTSTS") {
    __UTSBase_init(address(this), decimals());

    _setRouter(_router);
    _setChainConfig(_allowedChainIds, _chainConfigs);

    _mint(msg.sender, 1_000_000 * 10 ** decimals());
}

Then we need do define constructor. Since it is Token, we don't need a lot, just general UTS settings and ERC20 metadata.

We need setup _router address, that can be found here.

_allowedChainIds are simply whitelist of chain id's, where you are allowing to bridge tokens.

_chainConfigs is array of settings responsible for bridge settings. We described this config here.

In constructor we need to call __UTSBase_init function to initialize UTS Base contract. Also we need to set router and chain config.

We can skip setting router and chain configs in constructor, but before starting bridging we need to do it with relevant public functions.

After this step we need to override 3 functions: _mintTo, _burnFrom and _authorizeCall.

function _authorizeCall() internal override onlyOwner() {}

function _burnFrom(
    address spender,
    address from, 
    bytes memory /* to */, 
    uint256 amount, 
    uint256 /* dstChainId */, 
    bytes memory /* customPayload */
) internal override returns(uint256 bridgedAmount) {
    if (from != spender) _spendAllowance(from, spender, amount);

    _update(from, address(0), amount);

    return amount;
}

function _mintTo(
    address to,
    uint256 amount,
    bytes memory /* customPayload */,
    Origin memory /* origin */
) internal override returns(uint256 receivedAmount) {
    _update(address(0), to, amount);

    return amount;
}

So, here is very simple logic, in the outbounding bridge transaction, we need to burn tokens from from address (do not forget about ERC20 allowance check), in the inbounding redeem transaction, we need to mint tokens to receiver to address.

So, our contract is ready, now it can be deployed on networks and we can start bridging tokens between each chain.

You can find full code here