In a Native collection, when a new Item is minted, the generated objectId value corresponds, after hexadecimal conversion, to the address of the ERC20 token created.
//The function to call in a Native EthItem Collection is //function mint(uint256 amount, string calldata tokenName, string calldata tokenSymbol, string calldata objectUri, bool editable) external returns(uint256 newObjectId, address interoperableInterfaceAddress);//Let's suppose the call returns you the following values:var objectId ="115229128895248074900976864697884278495202009447";var interoperableInterfaceAddress ="0x142f0d872a9579c61098c783aed1c5f9404c6167"//The HEX version of the objectId is EXACTLY the address of the created ERC20 Tokenvar builtAddress =web3.utils.toHex(objectId);//-> will exactly return 0x142f0d872a9579c61098c783aed1c5f9404c6167, which is equal to the original interoperableInterfaceAddress value.//Now let's retrieve back the objectId from the interoperableInterfaceAddress//Convert in abivar abiEncodedValue =web3.eth.abi.encodeParameter('address', interoperableInterfaceAddress);//-> will generate the value "0x000000000000000000000000142f0d872a9579c61098c783aed1c5f9404c6167"//Convert in uint256var builtObjectId =web3.eth.abi.decodeParameter('uint256', abiEncodedValue);//-> will exactly return "115229128895248074900976864697884278495202009447", which is equal to the original objectId value.