Ethers.js Transactions – What Does Curly Bracket Mean in Smart Contract Transaction?

ethers.jsjavascriptreact

await routerContract
        .addLiquidityETH(
          daiAddress,
          ethers.utils.parseEther(strDaiAmount),
          ethers.utils.parseEther(strDaiSlippage),
          ethers.utils.parseEther(strEthSlippage),
          signerAddress,
          Date.now() + 60000 * props.deadline,
          { value: ethers.utils.parseEther(strEthAmount) }
        )

The above is working code. I am writing this question for further understanding.

I am having trouble understanding the final parameter of my smart contract… { value: ethers.utils.parseEther(strEthAmount) }

I added the final parameter as the code was throwing errors and I saw a thread saying that you have to add this parameter so that ethers knows that I am making a transaction. As far as I understand, the parameter is only passing the ether amount.

Another resolution that I tried was putting a .send method for my transaction. But ethers does not recognize the .send method.

If anyone could help to clear my confusion or give some pointers, I would be very grateful. Thanks!

Best Answer

addLiquidityETH seems to be a payable function therefore it needed that parameter, those curly brackets indicate that this is info for the transaction and not part of the parameters expected by the function, that's how you indicate you are sending eth. It could also include gasLimit and other properties.

Related Solutions

[Ethereum] Can’t send Ether to smart contract using Ethers.js

here is the error:

<input onChange={e => setWager(e.target.value)} placeholder="Send your ETH"/>

there is no "value" prop. you should have

<input 
value={wager}
onChange={e => setWager(e.target.value)} placeholder="Send your ETH"/>

You are not passing a valid input, that is why you are getting that error

Uniswap v3 – What Does ‘Price’ Mean in Uniswap v3 Trading?

So the whitepaper is great, but doesn't get into Token Decimals, since tokens will have different decimals, this must be taken into account

for tick to price (which is imprecise compared to sqrtPrice)

(1.0001**Math.abs(tick))/(10**Math.abs(token0Decimals-token1Decimals)) = Token0 price in relation to Token1

Price from sqrtPriceX96

and here is a script in mjs form, but math is extrapolatable

import { JSBI } from "@uniswap/sdk";
import { ethers } from 'ethers';
import * as fs from 'fs';

    // ERC20 abi
let ERC20Abi = fs.readFileSync('<path>/ERC20.json');
const ERC20 = JSON.parse(ERC20Abi);
    // V3 pair abi
let pool = fs.readFileSync('<path>/V3PairAbi.json');
const IUniswapV3PoolABI = JSON.parse(pool);
    // V3 factory abi
let facto = fs.readFileSync('<path>/V3factory.json');
const IUniswapV3FactoryABI = JSON.parse(facto);


const provider = new ethers.providers.JsonRpcProvider("https://eth-mainnet.alchemyapi.io/v2/<API_Key>")


const factory = "0x1F98431c8aD98523631AE4a59f267346ea31F984";


async function getPoolData(token0, token1, fee){
    const t0 = token0.toLowerCase() < token1.toLowerCase() ? token0 : token1;
    const t1 = token0.toLowerCase() < token1.toLowerCase() ? token1 : token0;
    const token0contract =  new ethers.Contract(t0, ERC20, provider);
    const token1contract =  new ethers.Contract(t1, ERC20, provider);
    const token0Decimal = await token0contract.decimals();
    const token1Decimal = await token1contract.decimals();
    const token0sym = await token0contract.symbol();
    const token1sym = await token1contract.symbol();
    const FactoryContract =  new ethers.Contract(factory, IUniswapV3FactoryABI, provider);
    const V3pool = await FactoryContract.getPool(token0, token1, fee);
    const poolContract =  new ethers.Contract(V3pool, IUniswapV3PoolABI, provider);
    const slot0 = await poolContract.slot0();
    const pairName = token0sym +"/"+ token1sym;
    return {"SqrtX96" : slot0.sqrtPriceX96.toString(), "Pair": pairName, "T0d": token0Decimal, "T1d": token1Decimal}
}


function GetPrice(testz){
    let sqrtPriceX96 = testz.SqrtX96;
    let token0Decimals = testz.T0d;
    let token1Decimals = testz.T1d;
    
    const buyOneOfToken0 = (sqrtPriceX96 * sqrtPriceX96 * (10**token0Decimals) / (10**token1Decimals) / JSBI.BigInt(2) ** (JSBI.BigInt(192))).toFixed(token1Decimals);
    const buyOneOfToken1 = (1 / buyOneOfToken0).toFixed(token0Decimals);
    console.log("price of token0 in value of token1 : " + buyOneOfToken0.toString());
    console.log("price of token1 in value of token0 : " + buyOneOfToken1.toString());
    //console.log("");
    
        // Convert to wei
    const buyOneOfToken0Wei = (Math.floor(buyOneOfToken0 * (10**token1Decimals))).toLocaleString('fullwide', {useGrouping:false});
    const buyOneOfToken1Wei = (Math.floor(buyOneOfToken1 * (10**token0Decimals))).toLocaleString('fullwide', {useGrouping:false});
    console.log("price of token0 in value of token1 in lowest decimal : " + buyOneOfToken0Wei);
    console.log("price of token1 in value of token1 in lowest decimal : " + buyOneOfToken1Wei);
    console.log("");
}


async function st(){
    const data = await getPoolData("0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "0xdAC17F958D2ee523a2206206994597C13D831ec7", 500);
    console.log(data)
    GetPrice(data)
}

st()

Best Answer

Related Solutions

[Ethereum] Can’t send Ether to smart contract using Ethers.js

Uniswap v3 – What Does ‘Price’ Mean in Uniswap v3 Trading?

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