Adding Liquidity Add liquidity to an existing HBAR/token liquidity pool.
Outlined below are two methods to add liquidity to an existing pool on SaucerSwap:
Ensure that the client has the LP token associated before adding liquidity.
A spender allowance for the Router contract is required for HTS tokens.
Both addLiquidityETH and addLiquidity support HTS tokens containing custom fees.
Adding HBAR/Token Liquidity
Add more liquidity to an existing HBAR/token liquidity pool.
Function name: addLiquidityETH
⛽ Recommended gas: 240,000 gwei (~ $0.020 USD)
Parameter Name Description EVM address of the token to pool with HBAR
The maximum token amount in its smallest unit
The minimum token amount in its smallest unit
The minimum HBAR amount in its smallest unit
EVM address to receive the liquidity tokens
Solidity Interface & Function Body
Copy //IUniswapV2Router01.sol
function addLiquidityETH (
address token ,
uint amountTokenDesired ,
uint amountTokenMin ,
uint amountETHMin ,
address to ,
uint deadline
) external payable returns ( uint amountToken , uint amountETH , uint liquidity);
Copy //UniswapV2Router02.sol
function addLiquidityETH (
address token ,
uint amountTokenDesired ,
uint amountTokenMin ,
uint amountETHMin ,
address to ,
uint deadline
) external virtual override payable ensure ( deadline ) returns ( uint amountToken , uint amountETH , uint liquidity) {
(amountToken , amountETH) = _addLiquidity (
token ,
whbar ,
amountTokenDesired ,
msg.value ,
amountTokenMin ,
amountETHMin
);
address pair = IUniswapV2Factory (factory). getPair (token , whbar);
require (pair != address ( 0 ) , "UniswapV2Router: PAIR DOES NOT EXIST" );
safeTransferToken (
token , msg.sender , pair , amountToken
);
IWHBAR (WHBAR).deposit{value : amountETH}(msg.sender , pair);
liquidity = IUniswapV2Pair (pair). mint (to);
// refund dust eth, if any
if (msg.value > amountETH) TransferHelper. safeTransferETH (msg.sender , msg.value - amountETH);
}
The addLiquidityETH function operates in HBAR but derives its name from Uniswap on Ethereum. This name was kept to simplify integration for developers versed in Uniswap tools.
Code Overview
Typescript
Resources:
Copy import {
ContractFunctionParameters ,
ContractExecuteTransaction ,
AccountAllowanceApproveTransaction ,
TokenAssociateTransaction ,
..
} from '@hashgraph/sdk' ;
//Client pre-checks:
// - Output NFT token is associated
// - Router contract has spender allowance for the input token
const params = new ContractFunctionParameters ();
params .addAddress (tokenAddress); //address token
params .addUint256 (amountTokenDesired); //uint amountTokenDesired
params .addUint256 (amountTokenMin); //uint amountTokenMin
params .addUint256 (amountHBARMin); //uint amountETHMin
params .addAddress (toAddress); //address to
params .addUint256 (deadline); //uint deadline
const response = await new ContractExecuteTransaction ()
.setPayableAmount (inputHbar)
.setContractId (routerContractId)
.setGas (gasLim)
.setFunction ( 'addLiquidityETH' , params)
.execute (client);
const record = await response .getRecord (client);
const result = record .contractFunctionResult ! ;
const values = result .getResult ([ 'uint' , 'uint' , 'uint' ]);
const amountToken = values[ 0 ]; //uint amountToken
const amountHBAR = values[ 1 ]; //uint amountETH
const liqudity = values[ 2 ]; //uint liquidity
Adding Token/Token Liquidity
Add more liquidity to an existing token/token liquidity pool.
Function name: addLiquidity
⛽ Recommended gas: 240,000 gwei (~ $0.020 USD)
Parameter Name Description EVM address of the first HTS token
EVM address of the second HTS token
The maximum amount for the first token in its smallest unit
The maximum amount for the second token in its smallest unit
The minimum amount for the first token in its smallest unit
The minimum amount for the second token in its smallest unit
EVM address to receive the liquidity tokens
Solidity Interface & Function Body
Copy //IUniswapV2Router01.sol
function addLiquidity (
address tokenA ,
address tokenB ,
uint amountADesired ,
uint amountBDesired ,
uint amountAMin ,
uint amountBMin ,
address to ,
uint deadline
) external returns ( uint amountA , uint amountB , uint liquidity);
Copy //UniswapV2Router02.sol
function addLiquidityNewPool (
address tokenA ,
address tokenB ,
uint amountADesired ,
uint amountBDesired ,
uint amountAMin ,
uint amountBMin ,
address to ,
uint deadline
) external virtual payable override ensure ( deadline ) returns ( uint amountA , uint amountB , uint liquidity) {
require ( IUniswapV2Factory (factory). getPair (tokenA , tokenB) == address ( 0 ) , "UniswapV2Router: POOL ALREADY EXISTS" );
address pair = IUniswapV2Factory (factory).createPair{value : msg.value}(tokenA , tokenB);
(amountA , amountB) = _addLiquidity (tokenA , tokenB , amountADesired , amountBDesired , amountAMin , amountBMin);
safeTransferToken (
tokenA , msg.sender , pair , amountA
);
safeTransferToken (
tokenB , msg.sender , pair , amountB
);
liquidity = IUniswapV2Pair (pair). mint (to);
}
Code Overview
Typescript
Resources:
Copy import {
ContractFunctionParameters ,
ContractExecuteTransaction ,
AccountAllowanceApproveTransaction ,
TokenAssociateTransaction ,
..
} from '@hashgraph/sdk' ;
//Client pre-checks:
// - Output NFT token is associated
// - Router contract has spender allowance for the input tokens
const params = new ContractFunctionParameters ();
params .addAddress (tokenAAddress); //address tokenA
params .addAddress (tokenBAddress); //address tokenB
params .addUint256 (amountADesired); //uint amountADesired
params .addUint256 (amountBDesired); //uint amountBDesired
params .addUint256 (amountAMin); //uint amountAMin
params .addUint256 (amountBMin); //uint amountBMin
params .addAddress (toAddress); //address to
params .addUint256 (deadline); //uint deadline
const response = await new ContractExecuteTransaction ()
.setContractId (routerContractId)
.setGas (gasLim)
.setFunction ( 'addLiquidity' , params)
.execute (client);
const record = await response .getRecord (client);
const result = record .contractFunctionResult ! ;
const values = result .getResult ([ 'uint' , 'uint' , 'uint' ]);
const amountA = values[ 0 ]; //uint amountA
const amountB = values[ 1 ]; //uint amountB
const liquidity = values[ 2 ]; //uint liquidity
Last updated 10 months ago