BlueToken-Hardhat_v1.0 (BTKn)

About

• The following specifications use syntax from Solidity 0.8.0 (or above)
• An ERC20 Token Faucet on the Rinkeby testnet.
• Adresse ERC20 - BlueToken : 0x85211679fDF491E18676B623db07cABCaF815316
• Adresse Faucet - BlueToken : 0xAD15db57F7342FD4CF80719013dBa63B378b4066
• Dapp GitHub address : https://github.com/ricardo-eth/BlueToken-Dapp_v1.0/tree/main
• The BlueToken Faucet has been deployed on Netlify : https://bluetoken-faucet.netlify.app

Features :

• Project set up using :

  "devDependencies": {
    "@nomiclabs/hardhat-ethers": "^2.0.2",
    "@nomiclabs/hardhat-solhint": "^2.0.0",
    "@nomiclabs/hardhat-waffle": "^2.0.1",
    "chai": "^4.3.4",
    "chalk": "^4.1.1",
    "dotenv": "^10.0.0",
    "eslint": "^7.28.0",
    "eslint-config-standard": "^16.0.3",
    "eslint-plugin-import": "^2.23.4",
    "eslint-plugin-mocha-no-only": "^1.1.1",
    "eslint-plugin-node": "^11.1.0",
    "eslint-plugin-promise": "^5.1.0",
    "eslint-plugin-standard": "^5.0.0",
    "ethereum-waffle": "^3.3.0",
    "ethers": "^5.3.1",
    "hardhat": "^2.3.3",
    "hardhat-docgen": "^1.1.1",
    "prettier": "^2.3.1",
    "prettier-plugin-solidity": "^1.0.0-beta.13",
    "solhint": "^3.3.6"
  },
  "dependencies": {
    "@openzeppelin/contracts": "^4.1.0"
  }

Install :

Clone Repo Git : https://github.com/ricardo-eth/BlueToken-Hardhat_v1.0/tree/main

% git clone git@github.com:ricardo-eth/BlueToken-Hardhat_v1.0.git
% cd BlueToken-Hardhat_v1.0

Install dependencies :

% yarn install

Test Smart contract :

% npx hardhat compile
% npx hardhat test

Contract ERC20 - BlueToken - BKTn

NOTE: Import ERC20 contract by OpenZeppelin : https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol

ERC20 - Function

Transfer :

Transfers value amount of tokens to address.

Requirements:

• recipient cannot be the zero address.
• the caller must have a balance of at least amount.

    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

TransferFrom :

Transfers value amount of tokens from address _from to address _to.

Requirements:

• sender and recipient cannot be the zero address.
• sender must have a balance of at least amount.
• the caller must have allowance for sender's tokens of at least amount.

  function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }

        return true;
      }

Approve :

Allows spender to withdraw from your account multiple times, up to the value amount.

Requirements:

• spender cannot be the zero address.

   function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

IncreaseAllowance :

Atomically increases the allowance granted to spender by the caller

Requirements:

• spender cannot be the zero address.

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }

DecreaseAllowance :

Atomically Decreases the allowance granted to spender by the caller

Requirements:

• spender cannot be the zero address.
• spender must have allowance for the caller of at least subtractedValue.

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }

ERC20 - Guetter

Name :

Returns the name of the token. "BlueToken".

    function name() public view virtual override returns (string memory) {
        return _name;
    }

Symbol :

Returns the symbol of the token. "BTKn".

  function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

Decimals :

Returns the number of decimals the token uses. 18, means to divide the token amount by 1000000000 to get its user representation.

    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

TotalSupply :

Returns the total token supply.

    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

BalanceOf :

Returns the account balance of another account.

    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

Allowance :

Returns the amount which _spender is still allowed to withdraw from _owner.

    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

Contract Faucet - BlueToken - BKTn

This contract has been deployed by the ERC20 BlueToken contract address

Faucet - Function

ClaimToken :

The claim function allows the user to retrieve their BKTn.

Requirements:

• _claimers must not have a cooldown.

    function claimToken() public {
        require(block.timestamp >= _claimers[msg.sender], "Faucet: you need to wait");
        _claimers[msg.sender] = block.timestamp + _delay;
        _token.transferFrom(owner(), msg.sender, _transferAmount);
        emit Claimed(msg.sender, _transferAmount);
    }

SetDelay :

The SetDelay function allows you to define the duration of the claim expressed in hours.

Requirements:

• onlyOwner The owner is the only one able to perform this function.

    function setDelay(uint48 newDelay_) public onlyOwner {
        _delay = newDelay_ * 1 hours;
    }

SetTransferAmount :

This function allows to define the amount to claim BlueToken.

Requirements:

• onlyOwner The owner is the only one able to perform this function.

    function setTransferAmount(uint128 newAmount_) public onlyOwner {
        _transferAmount = newAmount_;
    }

Faucet - Guetter

DelayOf :

Return Delay of _claimers address

    function delayOf(address claimer) public view returns (uint256) {
        return _claimers[claimer];
    }

Delay :

Return _delay of the claim.

  function delay() public view returns (uint48) {
        return _delay;
    }

TransferAmount :

Return the current value of the amount that users can BlueToken claim.

    function transferAmount() public view returns (uint128) {
        return _transferAmount;
    }

TimeRest :

Return Time for next BlueToken claim.

    function timeRest() public view returns (uint256) {
        return _claimers[msg.sender] > block.timestamp ? _claimers[msg.sender] - block.timestamp : 0;
    }