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Write (SmartContractExecution TxType)

Import the @kaiachain/ethers-ext modules to add kaia features on web3.

Initializes a public client for read-only interactions with the Kaia blockchain.

Set up a wallet client using createWalletClient, configured with the Kairos chain, an HTTP transport, and the sender’s private key converted to an account.

Set the Abi generated from solidity code

Define contract address to interact with

Encode the function name and parameter with the encodeFunctionData function

Create a transaction request for a value transfer using prepareTransactionRequest, specifying the sender’s account, recipient address, value to transfer (0 KLAY in this example), and transaction type (TxType.SmartContractExecution).

Send the transaction to the Kaia blockchain using the wallet client’s sendTransaction method, and log the transaction hash.

Uses the public client to query the number function (a view function that doesn’t modify state) from the contract. This retrieves the current value of the number variable, which should reflect the timestamp set by the previous transaction (if successful).

writeTxType.js


import {
    http,
    encodeFunctionData,
    createWalletClient, createPublicClient, kairos,
    TxType,
    privateKeyToAccount
} from "@kaiachain/viem-ext";
const publicClient = createPublicClient({
    chain: kairos,
    transport: http(),
});
const senderWallet = createWalletClient({
    chain: kairos,
    transport: http(),
    account: privateKeyToAccount(
        "0x0e4ca6d38096ad99324de0dde108587e5d7c600165ae4cd6c2462c597458c2b8"
    ),
});
// Example usage
(async () => {
    const contractAddr = "0x95Be48607498109030592C08aDC9577c7C2dD505";
    const abi = [{ "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 data = encodeFunctionData({
        abi,
        args: [Date.now()],
        functionName: "setNumber",
    });
    const tx = await senderWallet.prepareTransactionRequest({
        type: TxType.SmartContractExecution,
        account: senderWallet.account,
        to: contractAddr,
        value: 0,
        data,
    });
    console.log("preparedTx", tx);
    const sentTx = await senderWallet.sendTransaction(tx);
    console.log("contract interaction tx", sentTx);
    const result = await publicClient.readContract({
        address: contractAddr,
        abi,
        functionName: 'number'
    })
    console.log('Current contract value', result);
})();

output


❯ node writeTxType.js
preparedTx {
  type: 48,
  account: {
    address: '0xA2a8854b1802D8Cd5De631E690817c253d6a9153',
    nonceManager: undefined,
    sign: [AsyncFunction: sign],
    signAuthorization: [AsyncFunction: signAuthorization],
    signMessage: [AsyncFunction: signMessage],
    signTransaction: [AsyncFunction: signTransaction],
    signTypedData: [AsyncFunction: signTypedData],
    source: 'privateKey',
    type: 'local',
    publicKey: '0x04dc9dccbd788c00fa98f7f4082f2f714e799bc0c29d63f04d48b54fe6250453cdaf06ca34ae8714cf3dae06bacdb78c7c2d4054bd38961d40853cd5f15955da79'
  },
  to: '0x95Be48607498109030592C08aDC9577c7C2dD505',
  value: 0,
  data: '0x3fb5c1cb000000000000000000000000000000000000000000000000000001977cfdd996',
  from: '0xA2a8854b1802D8Cd5De631E690817c253d6a9153',
  nonce: 2399,
  chainId: 1001,
  gas: 27953n,
  gasPrice: '0x66720b300',
  gasLimit: 69882
}
contract interaction tx 0x1834bf6fb6fe30bbf1799b03db6dd5448b0bb445e503f38496845b995f909baa
Current contract value 1750147159253n