Writing Smart Contracts with Web3

Install web3 and solc dependencies

Before starting the deployment process, you need to install the packages for web3 and solc：

Install Node.js and npm: If you have already installed Node.js, you can check if npm is installed by running 'npm -v'. If you haven't installed Node.js yet, please download and install it from the official website:

https://nodejs.org/en/

Enter 'npm install web3' in the command line and press Enter. npm will automatically download and install the web3 package from the npm registry.

npm install web3

Install solc package: Enter 'npm install solc' in the command line and press Enter. npm will automatically download and install the solc package from the npm registry.

npm install solc

Write smart contracts.

Now you need to write a smart contract. Let's name this smart contract 'test1.sol'.

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.18;

contract Counter {

    // Public variable of type unsigned int to keep the number of counts
    uint256 public count = 0;

    // Function that increments our counter
    function increment() public {
        count += 1;
    }

    // Not necessary getter to get the count value
    function getCount() public view returns (uint256) {
        return count;
    }

}

Compile and deploy the contract

Write Node.js code to compile and deploy test1.sol.

const solc = require('solc');
const Web3 = require('web3');
const fs = require('fs');
//select a blockchain node
const web3 = new Web3('HTTP://127.0.0.1:7545');
// read the contract file
const contractCode = fs.readFileSync('./test1.sol', 'utf-8');
//compile the contract.
const input = {
    language: 'Solidity',
    sources: {
        'test1.sol': {
            content: contractCode,
        },
    },
    settings: {
        outputSelection: {
            '*': {
                '*': ['*']
            },
        },
    },
};
//get the bytecode of the smart contract
const output = JSON.parse(solc.compile(JSON.stringify(input)));
const bytecode = output.contracts['test1.sol']['test'].evm.bytecode.object
//define the ABI  of the smart contrac
const abi = output.contracts['test1.sol']['test'].abi;
//get an account for deploying the smart contract.
web3.eth.getAccounts().then(function(accounts) {
    const account = accounts[0];
    //deploy the smart contract
    const contract = new web3.eth.Contract(abi);
    contract.deploy({
      data: bytecode,
      arguments: []
    }).send({
      from: account,
      gas: 1500000,
      gasPrice: '30000000000000'
    }).then(function(newContractInstance) {
      console.log('Contract deployed at address: ' + newContractInstance.options.address);
    });
  });
```

Save the above code as 'test.js' and run it through Node.j，

node test.js

The returned result is：

Contract deployed at address: 0x9Cc053b6668a36A2C590Ff9b36abE63DaEDFd702

The smart contract has been successfully deployed.