Iterable Eternal Storage

iterable_eternal_storage.sol

addAddressKey("balanceKeys", "0x12...");

function addAddressKey(bytes32 _listId, address _value) external {
  // get the number of keys with _listId "balanceKeys"
  uint256 size = getUInt256(keccak256(abi.encodePacked(_listId, "KEY_SIZE")));
  
  // the new index (end of the list) is equal to the size of the keys
  uint256 index = size;
  
  // store _value as last item in the list
  setAddress(keccak256(abi.encodePacked(_listId, "KEY_VALUES", index)), _value);
  
  // increase the size of the list by one
  setUInt256(keccak256(abi.encodePacked(_listId, "KEY_SIZE")), size + 1);
}