⚠️Non-audited but open source contracts⚠️

TokenClient is a smart contract written in Solidity to support fungible and non-fungible token operations (such as sell/buy, swap, etc) in a generic way, making easy, quick, elegant, generic and future-proof implementations of token algorithms.

Support new standards in your logic by simply registering a contract address in the client, which inherits from TokenAbstraction. Your code interacts with the client instead of the ERC20, ERC721, or any other instance (the client will do it for you). So you don't need to commit your code to protocols, you can focus on the fun stuff, and make more elegant dapps by eliminating redundancy where all tokens share functionality (like isApproved or transfer or balanceOf), which is the functionality that many marketplaces and complex operators need to operate with tokens.

You can reference a TokenClient instance on your dapp or inherit from TokenClient contract. To support the standards you want, you have to register them on the client using some TokenAbstraction concrete, such as TokenERC20, TokenERC721 or TokenERC1155 (or creating your own), which have a few view functions, the transfer function and doesn't have storage. These are in charge of calling the methods of each standard, but you only have to make calls to your TokenClient instance, using methods such as isOwner, balanceOf, isApproved or transfer. Then you can focus on the logic of your dapp without worrying about standards support, separating this decision from the implementation and allowing it to be defined at any time.

• Easy to use, query and transfer any token from one instance.
• Quick to implement, focus on your contract logic and forget about standard specifications.
• Generic functionality, make your dapp operate generically with tokens.
• More elegant, reduces complexity and redundancy in your logic.
• Future-proof, your contract will be able to support any new token standard.
• Standard identification, recognize what type of token a contract address is.
• Transfer event, monitors when any token has been transferred.
• Call permission, controls from where the client can be called.
• Install as a package: npm i @danielabalde/token-client. The npm package is not being updated, while waiting for help from their technical support, please use: https://github.com/DanielAbalde/Token-Client/blob/891b99afa2273929fcef296d22df81c4650df972/contracts/TokenClient.sol to import the contract.

When you start a project that operated with NFT, such as swappers or marketplaces, you are faced with the dilemma of making the functionality specific to each standard or making it generic. In the first case it becomes a mess if you use proxies; and in the generic case there is extra work that each project has to do. In both cases, it makes sense to externalize this logic to save time and make it more elegant and advanced.

On the other hand, I am quite convinced that in a few years there will be new standards for NFT and fungible tokens, not only because of their current limitations, but also because replacing EOAs with contract-based accounts may improve the current patterns.

The shared functionality between standards is enough to help marketplaces and operators in many use cases. It can be extended particullary, as is the case of TokenERC721, where it includes the owner() function. Or you can extending it with a custom token concrete by inheriting from TokenAbstraction.

This is how the current shared functionality of TokenClient.sol looks like:

    function isStandard(address contractAddress) external view returns(bool);

    function isOwner(Token calldata token, address account) external view returns (bool);
    function balanceOf(Token calldata token, address account) external view returns (uint256);
    function isApproved(Token calldata token, address account, address operator) external view returns (bool);
    function transfer(Token calldata token, address from, address to) external returns (bool);
    
    function isOwnerSet(TokenSet calldata tokenSet, address account) external view returns (bool);
    function balanceOfSet(TokenSet calldata tokenSet, address account) external view returns (uint256[] memory);
    function isApprovedSet(TokenSet calldata tokenSet, address account, address operator) external view returns (bool);
    function transferSet(TokenSet calldata tokenSet, address from, address to) external returns (bool);

Token represents for fungibles a quantity of tokens, and for non-fungibles an identificable token. TokenSet represents for non-fungible a set of unique tokens. The token id is of type bytes32 instead of uint256 to support more powerful NFTs.

struct Token
{
   bytes32 Standard;
   address Contract;
   bytes32 Id;
   uint256 Amount;  
}

struct TokenSet
{
   bytes32 Standard;
   address Contract;
   bytes32[] Ids;
   uint256[] Amounts;  
}

Define token support for ERC20, ERC721 and ERC1155 in a minimal buy/sell mechanism:

   // using ethers.js and ./scripts/deploy.js

   const tokenClient = await deploy("TokenClient");

   const tokenERC20 = await deploy("TokenERC20");
   const tokenERC721 = await deploy("TokenERC721");
   const tokenERC1155 = await deploy("TokenERC1155");
          
   await tokenClient.support(tokenERC20.address);
   await tokenClient.support(tokenERC721.address);
   await tokenClient.support(tokenERC1155.address); 

   const market = await deploy("Market", tokenClient.address);

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

//import "@danielabalde/token-client/contracts/TokenClient.sol"; 
import "https://github.com/DanielAbalde/Token-Client/blob/891b99afa2273929fcef296d22df81c4650df972/contracts/TokenClient.sol";

contract Market
{
    struct Item
    {
        Token Token;
        uint256 Price;
        address Owner;
    } 
   
    TokenClient _client;

    mapping(uint256=>Item) _items;
    uint256 _itemCount;

    constructor(address tokenClient) {
        _client = TokenClient(tokenClient);
    }

    function sell(Token calldata token, uint256 price) external returns(uint256 id) {
        require(_client.isOwner(token, msg.sender), "Not the owner");
        require(_client.isApproved(token, msg.sender, address(_client)), "TokenClient not approved by owner");
        require(price > 0, "Price is zero"); 
        id = ++_itemCount;
        _items[id] = Item(token, price, msg.sender);
    }

    function buy(uint256 id) external payable {
        Item memory item = _items[id];
        require(item.Owner != address(0), "id not found");
        require(msg.value >= item.Price, "Not enough value");
        payable(item.Owner).transfer(msg.value);
        _client.transfer(item.Token, item.Owner, msg.sender);
    } 
}

npm i @danielabalde/token-client

• Challenge To Claim. Put tokens under a challenge such as a quiz, whoever solves or finds the solution claims the tokens.

• Issues and Pull Request on Github are welcome.
• Invite me a coffee at daniga.eth or 0x4443049b49Caf8Eb4E9235aA1Efe38FcFA0055a1
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• Give a ⭐ to this project!