web3js@4-dapp-backend.js

import Web3 from 'web3' // import web3
import fs from 'fs' // fs for saving file
import dotenv from 'dotenv' // parse envs

// bytecodes and abi artifacts
const abi = [...] as const
const GOLD = '0x...';
const SILVER = '0x...';
const USDT = '0x...'
const USDC = '0x...'
const SOME = '0x...'
const bytecodes = [GOLD, SILVER, USDT, USDC, SOME]

dotenv.config()

const init = async () => {
    const web3 = new Web3(process.env.REACT_APP_PROVIDER)
    // make account from private key
    const acc = web3.eth.accounts.privateKeyToAccount(String(process.env.REACT_APP_MAIN_PK))
    const myAcc = web3.eth.accounts.privateKeyToAccount(String(process.env.REACT_APP_PK))
    web3.eth.accounts.wallet.add(acc); // add account to a wallet

    const contractAddresses = []
    const contract = new web3.eth.Contract(abi)

    // generate ERC20 tokens
    for (const bytecode of bytecodes) {
        const transaction = contract.deploy({
            data: bytecode,
            arguments: ['1000000000000000000000'],
        })
        const gas = await transaction.estimateGas()

        const deployed = await transaction.send({from: acc.address, gas: gas.toString()})

        contractAddresses.push(deployed.options.address)
        // add some tokens to our account
        await deployed.methods.transfer(myAcc.address, String(web3.utils.toWei(Math.random() * 1000, 'ether'))).send({
            from: acc.address,
            gas: '2000000'
        })
    }


    // save results
    const fileName = './src/web3/addresses.json'
    if (fs.existsSync(fileName)) {
        fs.unlinkSync(fileName)
    }
    fs.writeFileSync(fileName, JSON.stringify(contractAddresses))
}

init().catch(console.error)