@kiwarilabs/contracts

A Solidity library for creating expirable tokens with time or block-based expiration.

• ERC-7818: Expirable ERC20
• ERC-7858: Expirable NFTs and SBTs

Installation

Install via npm

npm install --dev @kiwarilabs/contracts@stable

Install via yarn

yarn add --dev @kiwarilabs/contracts@stable

Example Usage

ERC-7818

Important

Some Layer 2 (L2) use precompiled contract or system contract for current block number instead of block.number.

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

import {ERC7818} from "@kiwarilabs/contracts/tokens/ERC20/ERC20EXPBase.sol";

contract MyToken is ERC7818 {
    constructor(
        string memory _name,
        string memory _symbol,
        uint40 blocksPerEpoch_,
        uint8 windowSize_
    ) ERC7818(_name, _symbol, block.number, blocksPerEpoch_, windowSize_, false) {}

    function epochType() internal pure virtual override returns (EPOCH_TYPE) {
        return EPOCH_TYPE.BLOCKS_BASED;
    }

    function _pointerProvider() internal view virtual override returns (uint256) {
        return block.number;
    }
}

ERC-7858

Individual Expiration

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

import {ERC7858} from "@kiwarilabs/contracts/tokens/ERC721/ERC7858.sol";

contract MyToken is ERC7858 {
    constructor (string memory name_, string memory symbol_) ERC7858(name_, symbol) {}

    function expiryType() public pure override returns (EXPIRY_TYPE) {
        return EXPIRY_TYPE.BLOCKS_BASED;
    }

    function _pointerProvider() internal view virtual override returns (uint256) {
        return block.number;
    }
}

Epoch Expiration

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

import {ERC7858Epoch} from "@kiwarilabs/contracts/tokens/ERC721/extensions/ERC7858Epoch.sol";

contract MyToken is ERC7858Epoch {
    constructor (
        string memory name_, 
        string memory symbol_, 
        uint256 initialBlockNumber_,
        uint40 blocksPerEpoch_,
        uint8 windowSize_)
        ERC7858Epoch(
            name_, 
            symbol_, 
            initialBlockNumber_,
            blocksPerEpoch_,
            windowSize_,
            development) {}

    function expiryType() public pure override returns (EXPIRY_TYPE) {
        return EXPIRY_TYPE.BLOCKS_BASED;
    }

    function _pointerProvider() internal view virtual override returns (uint256) {
        return block.number;
    }
}

Contribute

Check out the contribution guide

Support and Issue

For support or any inquiries, feel free to reach out to us at github-issue or kiwarilabs@protonmail.com

Funding

If you value our work and would like to support Kiwari Labs, please visit our Open Collective page to make a donation. Thank you!

License

This repository is released under the Apache-2.0.
Copyright (C) Kiwari Labs.