Web3js – How to Retrieve Current ERC20 Token Price from Uniswap V2 Router

erc-20uniswapweb3js

I'm really stuck on getting the price of a erc20 token for 1 wETH if the token can have a dynamic decimal.

I tried to play with values dividing them by token's exponentiation decimals in different ways. The value may be correct, for instance 18 decimals, but when it comes to 9 decimals, the value is wrong.

export async function getCurrentPrice(web3, tokenAddress) {
    const uniswapRouter = '0x10ED43C718714eb63d5aA57B78B54704E256024E'; // actually Pancakeswap but doesn't matter
    const routerContract = new web3.eth.Contract(
        router.abi,
        uniswapRouter);

    let tokenDecimals = await getTokenDecimals(web3, tokenAddress);

    const wETHTokenAddress = web3.utils.toChecksumAddress('0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c'); // actually wBNB but doesn't matter
    const amounts = await routerContract.methods.getAmountsOut(
        web3.utils.toWei('1', 'ether'),
        [tokenAddress, wETHTokenAddress]
    ).call();

    console.log('Token: ', tokenAddress, '| Decimals :', tokenDecimals) // -> The output is a correct value of token's decimals 
 
    // Tried different ways, also tried to divide while calling getAmountsOut in many ways and so on
    // let currentTokenPrice = parseFloat(web3.utils.fromWei(amounts[1], 'wei')) / (10 ** tokenDecimals);
    // return currentTokenPrice.toFixed(tokenDecimals);

    const outputAmount = web3.utils.fromWei(amounts[1], 'wei');
    const price = outputAmount / Math.pow(10, tokenDecimals);
    return price.toFixed(tokenDecimals);
}

Best Answer

In your code, you have mixed up the decimals in the input and the output of the swap. If you use getAmountsOut and swap from the token to WETH, then the number of the decimals in the input should be that of the token, and in the output that of WETH (always 18).

In addition, using getAmountsOut() to get the current price is not correct. This function includes the fee and slippage. To get the price of the token in terms of WETH (or vice versa), call getReserves() of the pair, divide the reserves with one other. There's also a quote helper function in the v2 library, but it's easy to implement offline. See this answer for some code on how to query the reserves. The result of the division reserveWETH/reserveToken is the raw price of WETH in terms of token. Multiply that with 10 ^ (decimals_token - 18) to get the UI price.

Related Solutions

[Ethereum] Uniswap Price Feed.- Get price of a Token in a Solidity contract

Uniswap has an SDK through which you can fetch the gas price. See their example in their documentation :

    import { ChainId, Token, WETH, Fetcher, Route } from '@uniswap/sdk'
    
    const DAI = new Token(ChainId.MAINNET, '0x6B175474E89094C44Da98b954EedeAC495271d0F', 18)
    
    // note that you may want/need to handle this async code differently,
    // for example if top-level await is not an option
    const pair = await Fetcher.fetchPairData(DAI, WETH[DAI.chainId])
    
    const route = new Route([pair], WETH[DAI.chainId])
    
    console.log(route.midPrice.toSignificant(6)) // 201.306
    console.log(route.midPrice.invert().toSignificant(6)) // 0.00496756

ERC-20 Deployment on Testnet – Fixing Deployment Issues with Uniswap Router

The error refers is storage out of gas. For bypass this error use can use the import of libraries.

Try this:

// SPDX-License-Identifier: Unlicensed 
pragma solidity ^0.8.4;
 
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol";
import "@uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol";
import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router01.sol";
import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";


library Address {
 
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }
 
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
 
        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
 
 
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }
 
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }
 
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
 
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        return _functionCallWithValue(target, data, value, errorMessage);
    }
 
    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");
 
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        if (success) {
            return returndata;
        } else {
 
            if (returndata.length > 0) {
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
 

contract CronosNaut is Context, IERC20, Ownable {
    using SafeMath for uint256;
    using Address for address;
 
    address payable public marketingAddress = payable(0x3bfC545BdE045e3eef6Ce2e75928946D7C5591f8); // Marketing Address
    address public immutable deadAddress = 0x000000000000000000000000000000000000dEaD;
    mapping (address => uint256) private _rOwned;
    mapping (address => uint256) private _tOwned;
    mapping (address => mapping (address => uint256)) private _allowances;
 
    mapping (address => bool) private _isExcludedFromFee;
 
    mapping (address => bool) private _isExcluded;
    address[] private _excluded;
 
    uint256 private constant MAX = ~uint256(0);
    uint256 private _tTotal = 1000000000 * 10**6 * 10**9;
    uint256 private _rTotal = (MAX - (MAX % _tTotal));
    uint256 private _tFeeTotal;
 
    string private _name = "CronosNaut";
    string private _symbol = "CRON";
    uint8 private _decimals = 9;
 
 
    uint256 public _taxFee = 2;
    uint256 private _previousTaxFee = _taxFee;
 
    uint256 public _liquidityFee = 2;
    uint256 private _previousLiquidityFee = _liquidityFee;
 
    uint256 public marketingDivisor = 2;
 
    uint256 public _maxTxAmount = 3000000 * 10**6 * 10**9;
    uint256 private minimumTokensBeforeSwap = 200000 * 10**6 * 10**9; 
    uint256 private buyBackUpperLimit = 1 * 10**18;
 
    IUniswapV2Router02 public immutable uniswapV2Router;
    address public immutable uniswapV2Pair;
 
    bool inSwapAndLiquify;
    bool public swapAndLiquifyEnabled = false;
    bool public buyBackEnabled = true;
 
 
    event RewardLiquidityProviders(uint256 tokenAmount);
    event BuyBackEnabledUpdated(bool enabled);
    event SwapAndLiquifyEnabledUpdated(bool enabled);
    event SwapAndLiquify(
        uint256 tokensSwapped,
        uint256 ethReceived,
        uint256 tokensIntoLiqudity
    );
 
    event SwapETHForTokens(
        uint256 amountIn,
        address[] path
    );
 
    event SwapTokensForETH(
        uint256 amountIn,
        address[] path
    );
 
    modifier lockTheSwap {
        inSwapAndLiquify = true;
        _;
        inSwapAndLiquify = false;
    }
 
    constructor () {
        _rOwned[_msgSender()] = _rTotal;
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
            .createPair(address(this), _uniswapV2Router.WETH());
 
        uniswapV2Router = _uniswapV2Router;
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
 
        emit Transfer(address(0), _msgSender(), _tTotal);
    }
 
    function name() public view returns (string memory) {
        return _name;
    }
 
    function symbol() public view returns (string memory) {
        return _symbol;
    }
 
    function decimals() public view returns (uint8) {
        return _decimals;
    }
 
    function totalSupply() public view override returns (uint256) {
        return _tTotal;
    }
 
    function balanceOf(address account) public view override returns (uint256) {
        if (_isExcluded[account]) return _tOwned[account];
        return tokenFromReflection(_rOwned[account]);
    }
 
    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
 
    function allowance(address owner, address spender) public view override returns (uint256) {
        return _allowances[owner][spender];
    }
 
    function approve(address spender, uint256 amount) public override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
 
    function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }
 
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }
 
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }
 
    function isExcludedFromReward(address account) public view returns (bool) {
        return _isExcluded[account];
    }
 
    function totalFees() public view returns (uint256) {
        return _tFeeTotal;
    }
 
    function minimumTokensBeforeSwapAmount() public view returns (uint256) {
        return minimumTokensBeforeSwap;
    }
 
    function buyBackUpperLimitAmount() public view returns (uint256) {
        return buyBackUpperLimit;
    }
 
    function deliver(uint256 tAmount) public {
        address sender = _msgSender();
        require(!_isExcluded[sender], "Excluded addresses cannot call this function");
        (uint256 rAmount,,,,,) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rTotal = _rTotal.sub(rAmount);
        _tFeeTotal = _tFeeTotal.add(tAmount);
    }
 
 
    function reflectionFromToken(uint256 tAmount, bool deductTransferFee) public view returns(uint256) {
        require(tAmount <= _tTotal, "Amount must be less than supply");
        if (!deductTransferFee) {
            (uint256 rAmount,,,,,) = _getValues(tAmount);
            return rAmount;
        } else {
            (,uint256 rTransferAmount,,,,) = _getValues(tAmount);
            return rTransferAmount;
        }
    }
 
    function tokenFromReflection(uint256 rAmount) public view returns(uint256) {
        require(rAmount <= _rTotal, "Amount must be less than total reflections");
        uint256 currentRate =  _getRate();
        return rAmount.div(currentRate);
    }
 
    function excludeFromReward(address account) public onlyOwner() {
 
        require(!_isExcluded[account], "Account is already excluded");
        if(_rOwned[account] > 0) {
            _tOwned[account] = tokenFromReflection(_rOwned[account]);
        }
        _isExcluded[account] = true;
        _excluded.push(account);
    }
 
    function includeInReward(address account) external onlyOwner() {
        require(_isExcluded[account], "Account is already excluded");
        for (uint256 i = 0; i < _excluded.length; i++) {
            if (_excluded[i] == account) {
                _excluded[i] = _excluded[_excluded.length - 1];
                _tOwned[account] = 0;
                _isExcluded[account] = false;
                _excluded.pop();
                break;
            }
        }
    }
 
    function _approve(address owner, address spender, uint256 amount) private {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
 
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
 
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) private {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");
        if(from != owner() && to != owner()) {
            require(amount <= _maxTxAmount, "Transfer amount exceeds the maxTxAmount.");
        }
 
        uint256 contractTokenBalance = balanceOf(address(this));
        bool overMinimumTokenBalance = contractTokenBalance >= minimumTokensBeforeSwap;
 
        if (!inSwapAndLiquify && swapAndLiquifyEnabled && to == uniswapV2Pair) {
            if (overMinimumTokenBalance) {
                contractTokenBalance = minimumTokensBeforeSwap;
                swapTokens(contractTokenBalance);    
            }
            uint256 balance = address(this).balance;
            if (buyBackEnabled && balance > uint256(1 * 10**18)) {
 
                if (balance > buyBackUpperLimit)
                    balance = buyBackUpperLimit;
 
                buyBackTokens(balance.div(100));
            }
        }
 
        bool takeFee = true;
 
        //if any account belongs to _isExcludedFromFee account then remove the fee
        if(_isExcludedFromFee[from] || _isExcludedFromFee[to]){
            takeFee = false;
        }
 
        _tokenTransfer(from,to,amount,takeFee);
    }
 
    function swapTokens(uint256 contractTokenBalance) private lockTheSwap {
 
        uint256 initialBalance = address(this).balance;
        swapTokensForEth(contractTokenBalance);
        uint256 transferredBalance = address(this).balance.sub(initialBalance);
 
        //Send to Marketing address
        transferToAddressETH(marketingAddress, transferredBalance.div(_liquidityFee).mul(marketingDivisor));
 
    }
 
 
    function buyBackTokens(uint256 amount) private lockTheSwap {
        if (amount > 0) {
            swapETHForTokens(amount);
        }
    }
 
    function swapTokensForEth(uint256 tokenAmount) private {
        // generate the uniswap pair path of token -> weth
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
 
        _approve(address(this), address(uniswapV2Router), tokenAmount);
 
        // make the swap
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, // accept any amount of ETH
            path,
            address(this), // The contract
            block.timestamp
        );
 
        emit SwapTokensForETH(tokenAmount, path);
    }
 
    function swapETHForTokens(uint256 amount) private {
        // generate the uniswap pair path of token -> weth
        address[] memory path = new address[](2);
        path[0] = uniswapV2Router.WETH();
        path[1] = address(this);
 
      // make the swap
        uniswapV2Router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: amount}(
            0, // accept any amount of Tokens
            path,
            deadAddress, // Burn address
            block.timestamp.add(300)
        );
 
        emit SwapETHForTokens(amount, path);
    }
 
    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        // approve token transfer to cover all possible scenarios
        _approve(address(this), address(uniswapV2Router), tokenAmount);
 
        // add the liquidity
        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            owner(),
            block.timestamp
        );
    }
 
    function _tokenTransfer(address sender, address recipient, uint256 amount,bool takeFee) private {
        if(!takeFee)
            removeAllFee();
 
        if (_isExcluded[sender] && !_isExcluded[recipient]) {
            _transferFromExcluded(sender, recipient, amount);
        } else if (!_isExcluded[sender] && _isExcluded[recipient]) {
            _transferToExcluded(sender, recipient, amount);
        } else if (_isExcluded[sender] && _isExcluded[recipient]) {
            _transferBothExcluded(sender, recipient, amount);
        } else {
            _transferStandard(sender, recipient, amount);
        }
 
        if(!takeFee)
            restoreAllFee();
    }
 
    function _transferStandard(address sender, address recipient, uint256 tAmount) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }
 
    function _transferToExcluded(address sender, address recipient, uint256 tAmount) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _tOwned[recipient] = _tOwned[recipient].add(tTransferAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);           
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }
 
    function _transferFromExcluded(address sender, address recipient, uint256 tAmount) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity) = _getValues(tAmount);
        _tOwned[sender] = _tOwned[sender].sub(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);   
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }
 
    function _transferBothExcluded(address sender, address recipient, uint256 tAmount) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity) = _getValues(tAmount);
        _tOwned[sender] = _tOwned[sender].sub(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _tOwned[recipient] = _tOwned[recipient].add(tTransferAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);        
        _takeLiquidity(tLiquidity);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }
 
    function _reflectFee(uint256 rFee, uint256 tFee) private {
        _rTotal = _rTotal.sub(rFee);
        _tFeeTotal = _tFeeTotal.add(tFee);
    }
 
    function _getValues(uint256 tAmount) private view returns (uint256, uint256, uint256, uint256, uint256, uint256) {
        (uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity) = _getTValues(tAmount);
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee) = _getRValues(tAmount, tFee, tLiquidity, _getRate());
        return (rAmount, rTransferAmount, rFee, tTransferAmount, tFee, tLiquidity);
    }
 
    function _getTValues(uint256 tAmount) private view returns (uint256, uint256, uint256) {
        uint256 tFee = calculateTaxFee(tAmount);
        uint256 tLiquidity = calculateLiquidityFee(tAmount);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tLiquidity);
        return (tTransferAmount, tFee, tLiquidity);
    }
 
    function _getRValues(uint256 tAmount, uint256 tFee, uint256 tLiquidity, uint256 currentRate) private pure returns (uint256, uint256, uint256) {
        uint256 rAmount = tAmount.mul(currentRate);
        uint256 rFee = tFee.mul(currentRate);
        uint256 rLiquidity = tLiquidity.mul(currentRate);
        uint256 rTransferAmount = rAmount.sub(rFee).sub(rLiquidity);
        return (rAmount, rTransferAmount, rFee);
    }
 
    function _getRate() private view returns(uint256) {
        (uint256 rSupply, uint256 tSupply) = _getCurrentSupply();
        return rSupply.div(tSupply);
    }
 
    function _getCurrentSupply() private view returns(uint256, uint256) {
        uint256 rSupply = _rTotal;
        uint256 tSupply = _tTotal;      
        for (uint256 i = 0; i < _excluded.length; i++) {
            if (_rOwned[_excluded[i]] > rSupply || _tOwned[_excluded[i]] > tSupply) return (_rTotal, _tTotal);
            rSupply = rSupply.sub(_rOwned[_excluded[i]]);
            tSupply = tSupply.sub(_tOwned[_excluded[i]]);
        }
        if (rSupply < _rTotal.div(_tTotal)) return (_rTotal, _tTotal);
        return (rSupply, tSupply);
    }
 
    function _takeLiquidity(uint256 tLiquidity) private {
        uint256 currentRate =  _getRate();
        uint256 rLiquidity = tLiquidity.mul(currentRate);
        _rOwned[address(this)] = _rOwned[address(this)].add(rLiquidity);
        if(_isExcluded[address(this)])
            _tOwned[address(this)] = _tOwned[address(this)].add(tLiquidity);
    }
 
    function calculateTaxFee(uint256 _amount) private view returns (uint256) {
        return _amount.mul(_taxFee).div(
            10**2
        );
    }
 
    function calculateLiquidityFee(uint256 _amount) private view returns (uint256) {
        return _amount.mul(_liquidityFee).div(
            10**2
        );
    }
 
    function removeAllFee() private {
        if(_taxFee == 0 && _liquidityFee == 0) return;
 
        _previousTaxFee = _taxFee;
        _previousLiquidityFee = _liquidityFee;
 
        _taxFee = 0;
        _liquidityFee = 0;
    }
 
    function restoreAllFee() private {
        _taxFee = _previousTaxFee;
        _liquidityFee = _previousLiquidityFee;
    }
 
    function isExcludedFromFee(address account) public view returns(bool) {
        return _isExcludedFromFee[account];
    }
 
    function excludeFromFee(address account) public onlyOwner {
        _isExcludedFromFee[account] = true;
    }
 
    function includeInFee(address account) public onlyOwner {
        _isExcludedFromFee[account] = false;
    }
 
    function setTaxFeePercent(uint256 taxFee) external onlyOwner() {
        _taxFee = taxFee;
    }
 
    function setLiquidityFeePercent(uint256 liquidityFee) external onlyOwner() {
        _liquidityFee = liquidityFee;
    }
 
    function setMaxTxAmount(uint256 maxTxAmount) external onlyOwner() {
        _maxTxAmount = maxTxAmount;
    }
 
    function setMarketingDivisor(uint256 divisor) external onlyOwner() {
        marketingDivisor = divisor;
    }
 
    function setNumTokensSellToAddToLiquidity(uint256 _minimumTokensBeforeSwap) external onlyOwner() {
        minimumTokensBeforeSwap = _minimumTokensBeforeSwap;
    }
 
     function setBuybackUpperLimit(uint256 buyBackLimit) external onlyOwner() {
        buyBackUpperLimit = buyBackLimit * 10**18;
    }
 
    function setMarketingAddress(address _marketingAddress) external onlyOwner() {
        marketingAddress = payable(_marketingAddress);
    }
 
    function setSwapAndLiquifyEnabled(bool _enabled) public onlyOwner {
        swapAndLiquifyEnabled = _enabled;
        emit SwapAndLiquifyEnabledUpdated(_enabled);
    }
 
    function setBuyBackEnabled(bool _enabled) public onlyOwner {
        buyBackEnabled = _enabled;
        emit BuyBackEnabledUpdated(_enabled);
    }
 
    function prepareForPreSale() external onlyOwner {
        setSwapAndLiquifyEnabled(false);
        _taxFee = 0;
        _liquidityFee = 0;
        _maxTxAmount = 1000000000 * 10**6 * 10**9;
    }
 
    function afterPreSale() external onlyOwner {
        setSwapAndLiquifyEnabled(true);
        _taxFee = 2;
        _liquidityFee = 8;
        _maxTxAmount = 3000000 * 10**6 * 10**9;
    }
 
    function transferToAddressETH(address payable recipient, uint256 amount) private {
        recipient.transfer(amount);
    }
 
     //to recieve ETH from uniswapV2Router when swaping
    receive() external payable {}
}

I only import the libraries with import keyword (the smart contract code is the same of pastebin).

Best Answer

Related Solutions

[Ethereum] Uniswap Price Feed.- Get price of a Token in a Solidity contract

ERC-20 Deployment on Testnet – Fixing Deployment Issues with Uniswap Router

Related Topic