I have an input field for the user to fill in gasPrice, which is 10 by default. When wallet.sendTransaction is placed in gasPrice or maxFeePerGas?

[linxianxi]

If the user enters 11, which one is it?

wallet.sendTransaction({ gasPrice: "11" })

or

wallet.sendTransaction({ maxFeePerGas: "11"  })

or

wallet.sendTransaction({ gasPrice: "11", maxFeePerGas: "11"  })

If there is no input box, use getFeeData to get gasPrice. What are the estimated gasFee that are presented to the user？

const feeData  = await provider.getFeeData();

const gasFee = feeData.gasPrice.mul(gasLimit);

or 

const gasFee = feeData.maxFeePerGas.mul(gasLimit);

[zemse]

If user mean 11 "gwei", then number actually looks like 11000000000, and there is a util in ethers to convert: ethers.utils.parseUnits('11', 'gwei').

Which networks would your code be targeted to? If it's always EIP1559: then you can specify:

// if wallet is connected to a provider it should populate max priority fee, otherwise have to be specified
await wallet.sendTransaction({ 
  maxFeePerGas: ethers.utils.parseUnits('11', 'gwei'),
})

// for max fee amount estimation
const gasFee = feeData.maxFeePerGas.mul(gasLimit);

But if network does not support EIP1559, then you have to specify gasPrice.

[itsmesoh]

Hi @zemse

Thank you for the replies. I have a small query.
In max fee amount estimation, how can I estimate the gasLimit ?

[zemse]

how can I estimate the gasLimit ?

The gasLimit is independent of the gas pricing (type0 gasPrice or type2 maxFeePerGas stuff). You can calculate it using estimateGas.

const gasLimit = await contract.estimateGas.transfer(receiver, amount);

// or

const gasLimt = await provider.estimateGas({to: dest, data: '0xData'});

[itsmesoh]

Thank you @zemse for your response.

In this ,
const gasLimt = await provider.estimateGas({to: dest, data: '0xData'});

What is "data"?

[zemse]

It's the input calldata, if you are interacting with a contract, it probably expects some input. e.g. for the erc20 transfer function, you can generate the input calldata as follows:

const {data} = await tokenContract.populateTransaction.transfer(receiver, amount);

If your transaction does not need an input you can just skip that prop

const gasLimt = await provider.estimateGas({to: dest});