Craft tx

craft.js

const ethers = require('ethers');
const { Interface } = require('ethers/lib/utils');
const contractAddress = '';

const key = '';
const RPC_SERVER = '';

async function main () {
    try {
        const provider = new ethers.providers.JsonRpcProvider(RPC_SERVER);
        const signer = new ethers.Wallet(key, provider);

        const EXTRA_ADDRESS = ethers.Wallet.createRandom();

        // function myFn(uint256 _amount) external
        let iface = new Interface(['function myFn(uint256)']);
        let inputData = ethers.utils.defaultAbiCoder.encode(["uint256","address"],[1, EXTRA_ADDRESS.address]);

        inputData = iface.getSighash('myFn')+inputData.slice(2);

         const txParams = {
            to: contractAddress, 
            data: inputData,
           };

       let tx = await signer.sendTransaction(txParams);
       await tx.wait()

    } catch (e) {
      console.log(e);
    }
}

main();

process.on('exit', function(code) {
  return console.log(`Exit with code ${code}`);
});

process.on('SIGINT', _ => {
  process.exit();
});