Building a raw contract transaction with ethers.js

Question

Can't find any good documentation on creating a raw transaction with contract data in ethers.js. The equivalent in web3 is adding the encodeABI on the data property. Any guidance on this?

This isn't working:

data = myContract.interface.functions.myFunction(value);
const tx = {
   ...
   data
   ...
}

It doesn't seem to recognize this is a function (even though i see the data property there).

Answer 1

You can use the populateTransaction mechanism documented here: https://docs.ethers.io/v5/api/contract/contract/

So specifically, that'd be:

const data = await myContract.populateTransaction.myFunction(value);

Answer 2

The way you can use populateTransaction in Ether.js is:

const contract = new Contract(CONTRACT_ADDRESS, CONTRACT_ABI, Wallet);
const params = [value];
const action = 'myFunction';
const unsignedTx = await contract.populateTransaction[action](...params);

Then you can simply sign and send your transaction like:

await Wallet.sendTransaction(unsignedTx);