Read

You can call functions in Smart Contract via "Call" RPC API. What you can call here is limited to view functions that is not changing any states in the Contract.

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

Set up the provider with the specified kaia Baobab testnet URL. A provider in web3js is a read-only abstraction to access the blockchain data.

Also, you can change the provider URL from baobab to allthatnode

Define contract Abi and addreess, you can get it from compiled solidity code

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

Call function number of created contract and print the result

smartContractRead.js

const { Web3 } = require("@kaiachain/web3js-ext");

const provider = new Web3.providers.HttpProvider("https://public-en-kairos.node.kaia.io");

const web3 = new Web3(provider);

/* 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);

const number = await contract.methods.number().call();

console.log("number", number.toString());

}

main();

output

❯ node smartContractRead.js

number 294