Deploy and call a smart contract using Nil.js

These recipes showcase how to use Nil.js to deploy and call a smart contract.

Create a smart contract

This example uses the standard counter contract:

pragma solidity ^0.8.0;

contract Counter {
    uint256 private value;

    event ValueChanged(uint256 newValue);

    receive() external payable {}

    function increment() public {
        value += 1;
        emit ValueChanged(value);
    }

    function getValue() public view returns (uint256) {
        return value;
    }

    function verifyExternal(
        uint256 hash,
        bytes memory authData
    ) external pure returns (bool) {
        return true;
    }
}

Import statements

Import the following components from @nilfoundation/niljs:

import {
  ExternalTransactionEnvelope,
  HttpTransport,
  PublicClient,
  bytesToHex,
  externalDeploymentTransaction,
  generateSmartAccount,
  getContract,
  hexToBytes,
  topUp,
  waitTillCompleted,
} from "@nilfoundation/niljs";

import { type Abi, encodeFunctionData } from "viem";

Deploy the contract

Internal deployment

To create a new smart account and deploy the contract internally:

const SALT = BigInt(Math.floor(Math.random() * 10000));

const client = new PublicClient({
  transport: new HttpTransport({
    endpoint: RPC_ENDPOINT,
  }),
  shardId: 1,
});

const smartAccount = await generateSmartAccount({
  shardId: 1,
  rpcEndpoint: RPC_ENDPOINT,
  faucetEndpoint: FAUCET_ENDPOINT,
});

const { address, hash } = await smartAccount.deployContract({
  bytecode: COUNTER_BYTECODE,
  abi: COUNTER_ABI,
  args: [],
  feeCredit: 50_000_000n,
  salt: SALT,
  shardId: 1,
});

const manufacturerReceipts = await waitTillCompleted(client, hash);

External deployment

To deploy the contract externally:

const SALT = BigInt(Math.floor(Math.random() * 10000));

const client = new PublicClient({
  transport: new HttpTransport({
    endpoint: RPC_ENDPOINT,
  }),
  shardId: 1,
});

const chainId = await client.chainId();

const deploymentTransaction = externalDeploymentTransaction(
  {
    salt: SALT,
    shard: 1,
    bytecode: COUNTER_BYTECODE,
    abi: COUNTER_ABI,
    args: [],
  },
  chainId,
);

const addr = bytesToHex(deploymentTransaction.to);

await topUp({
  address: addr,
  faucetEndpoint: FAUCET_ENDPOINT,
  rpcEndpoint: RPC_ENDPOINT,
});

const hash = await deploymentTransaction.send(client);

const receipts = await waitTillCompleted(client, hash);

Sending a transaction to the contract

Via the contract factory

Nil.js can utilize a special 'contract factory' to interact with smart contracts in a manner similar to a Hardhat task:

const contract = getContract({
  client: client,
  abi: COUNTER_ABI as unknown[],
  address: COUNTER_ADDRESS,
  smartAccount: smartAccount,
});

const res = await contract.read.getValue([]);
expect(res).toBe(0n);

const hash = await contract.write.increment([]);
await waitTillCompleted(client, hash);

const res2 = await contract.read.getValue([]);

console.log(res2);

Internal transaction

To send a new internal transaction to the increment() function:

const hash = await smartAccount.sendTransaction({
  to: COUNTER_ADDRESS,
  abi: COUNTER_ABI,
  functionName: "increment",
});

const receipts = await waitTillCompleted(client, hash);

External transaction

To send a new external transaction to the increment() function:

const transaction = new ExternalTransactionEnvelope({
  to: hexToBytes(COUNTER_ADDRESS),
  isDeploy: false,
  chainId,
  data: hexToBytes(
    encodeFunctionData({
      abi: COUNTER_ABI,
      functionName: "increment",
      args: [],
    }),
  ),
  authData: new Uint8Array(0),
  seqno: await client.getTransactionCount(COUNTER_ADDRESS),
});

const encodedTransaction = transaction.encode();

let success = false;
let transactionHash: `0x${string}`;

while (!success) {
  try {
    transactionHash = await client.sendRawTransaction(bytesToHex(encodedTransaction));
    success = true;
  } catch (error) {
    await new Promise((resolve) => setTimeout(resolve, 1000));
  }
}

const receipts = await waitTillCompleted(client, transactionHash);