Write with TxType

Import the web3 and @kaiachain/web3js-ext packages to add kaia features on web3

Define sender's address and private key

Set up the provider with the specified kairos testnet URL. A provider in web3 is a read-only abstraction to access the blockchain data.

Also, you can change the provider URL from kairos to quicknode

Create a sender's account using web3.eth.accounts.privateKeyToAccount

Define contract Abi and address to interact with

Create a contract instance using Web3.eth.Contract with defined contractAbi and address. You can read and write the contract through this instance

Get the number before update

Encoded the contract method data with contract.methods.increment().encodeABI()

Create a transaction to update the value number with type: FeeDelegatedSmartContractExecution

Sign the transaction with sender account

Send the transaction to network and wait for the receipt

Get the number after update

smartContractWriteWithTxType.js


const { Web3, TxType } = require("@kaiachain/web3js-ext");
const senderAddr = "0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7";
const senderPriv = "0x4a72b3d09c3d5e28e8652e0111f9c4ce252e8299aad95bb219a38eb0a3f4da49";
const provider = new Web3.providers.HttpProvider("https://public-en-kairos.node.kaia.io");
const web3 = new Web3(provider);
const senderAccount = web3.eth.accounts.privateKeyToAccount(senderPriv);
/* compiled in remix.ethereum.org (compiler: 0.8.18, optimizer: false)
// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.13;
contract Counter {
    uint256 public number;
    event SetNumber(uint256 number);
    constructor(uint256 initNumber) {
        number = initNumber;
    }
    function setNumber(uint256 newNumber) public {
        number = newNumber;
        emit SetNumber(number);
    }
    function increment() public {
        number++;
        emit SetNumber(number);
    }
}
*/
const contractAbi = JSON.parse('[{"inputs":[{"internalType":"uint256","name":"initNumber","type":"uint256"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"number","type":"uint256"}],"name":"SetNumber","type":"event"},{"inputs":[],"name":"increment","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"number","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"newNumber","type":"uint256"}],"name":"setNumber","outputs":[],"stateMutability":"nonpayable","type":"function"}]');
const contractAddr = "0x95Be48607498109030592C08aDC9577c7C2dD505";
async function main() {
  const contract = new web3.eth.Contract(contractAbi, contractAddr);
  console.log("number before", (await contract.methods.number().call()).toString());
  const data = contract.methods.increment().encodeABI();
  const tx = {
    type: TxType.SmartContractExecution,
    from: senderAddr,
    to: contractAddr,
    data: data,
  };
  const signResult = await senderAccount.signTransaction(tx);
  console.log("signedTx", signResult.transactionHash);
  const receipt = await web3.eth.sendSignedTransaction(signResult.rawTransaction);
  console.log("receipt", receipt);
  console.log("number after", (await contract.methods.number().call()).toString());
}
main();

output


❯ node smartContractWriteWithTxType.js
number before 295
signedTx 0xb4e2f9d3a6c3d24a318028ff904f2d21e79ca6f2adc41aa099cd1be70f7952b9
receipt {
  blockHash: '0xdbf4c6d306da99f7c36500d0ec84d0064b34820f51e827a4f6662f1b734a27cf',
  blockNumber: 148743668n,
  cumulativeGasUsed: 28014n,
  effectiveGasPrice: 25000000000n,
  from: '0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7',
  gasUsed: 28014n,
  logs: [
    {
      address: '0x95be48607498109030592c08adc9577c7c2dd505',
      topics: [Array],
      data: '0x0000000000000000000000000000000000000000000000000000000000000128',
      blockNumber: 148743668n,
      transactionHash: '0xb4e2f9d3a6c3d24a318028ff904f2d21e79ca6f2adc41aa099cd1be70f7952b9',
      transactionIndex: 0n,
      blockHash: '0xdbf4c6d306da99f7c36500d0ec84d0064b34820f51e827a4f6662f1b734a27cf',
      logIndex: 0n,
      removed: false
    }
  ],
  logsBloom: '0x00000000000040000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000000000000001200000002',
  status: 1n,
  to: '0x95be48607498109030592c08adc9577c7c2dd505',
  transactionHash: '0xb4e2f9d3a6c3d24a318028ff904f2d21e79ca6f2adc41aa099cd1be70f7952b9',
  transactionIndex: 0n,
  type: 0n
}
number after 296