tokenTransfer.js

const fs = require('fs');
const path = require('path');
const Web3API = require('web3');
const axios = require('axios');

/**
 * Fetch the current transaction gas prices from https://ethgasstation.info/
 * 
 * @return {object} Gas prices at different priorities
 */
const getCurrentGasPrices = async () => {
    let response = await axios.get('https://ethgasstation.info/json/ethgasAPI.json');
    let prices = {
        low: response.data.safeLow / 10,
        medium: response.data.average / 10,
        high: response.data.fast / 10
    };

    console.log("\r\n");
    console.log(`Current ETH Gas Prices (in GWEI):`);
    console.log("\r\n");
    console.log(`Low: ${prices.low} (transaction completes in < 30 minutes)`);
    console.log(`Standard: ${prices.medium} (transaction completes in < 5 minutes)`);
    console.log(`Fast: ${prices.high} (transaction completes in < 2 minutes)`);
    console.log("\r\n");

    return prices
};

export default async () => {
    const web3 = new Web3API(new Web3API.providers.HttpProvider('https://mainnet.infura.io'));
    const privateKey = "0x..";
    const tokenAddress = "0x..";
    const fromAddress = "0x..";
    const toAddress = "0x..";

    // ABI to transfer ERC20 Token
    let abi = JSON.parse(fs.readFileSync(path.join(__dirname, '.', 'main_contract.json'), 'utf-8'));
    // calculate ERC20 token amount
    let amount = 1;
    let tokenAmount = web3.utils.toWei(amount.toString(), 'ether')
    // Get ERC20 Token contract instance
    let contract = new web3.eth.Contract(abi, tokenAddress, {
        from: fromAddress
    });
    // How many tokens do I have before sending?
    let balance = await contract.methods.balanceOf(fromAddress).call();
    console.log(`Balance before send: ${balance}`);
    // EIP 155 - List of Chain ID's:
    const chainList = {
        mainnet: 1,
        morden: 2,
        ropsten: 3,
        rinkeby: 4,
        ubiqMainnet: 8,
        ubiqTestnet: 9,
        rootstockMainnet: 30,
        rootstockTestnet: 31,
        kovan: 42,
        ethereumClassicMainnet: 61,
        ethereumClassicTestnet: 62,
        ewasmTestnet: 66,
        gethPrivateChains: 1337
    };
    // The gas price is determined by the last few blocks median gas price.
    const avgGasPrice = await web3.eth.getGasPrice();
    // current transaction gas prices from https://ethgasstation.info/
    const currentGasPrices = await getCurrentGasPrices();
    /**
     * With every new transaction you send using a specific wallet address,
     * you need to increase a nonce which is tied to the sender wallet.
     */
    let nonce = web3.eth.getTransactionCount(fromAddress);
    // Will call estimate the gas a method execution will take when executed in the EVM without.
    let estimateGas = await web3.eth.estimateGas({
        "value": '0x0', // Only tokens
        "data": contract.methods.transfer(toAddress, tokenAmount).encodeABI(),
        "from": fromAddress,
        "to": toAddress
    });
    console.log({
        estimateGas: estimateGas
    });
    // Build a new transaction object.
    const transaction = {
        "value": '0x0', // Only tokens
        "data": contract.methods.transfer(toAddress, tokenAmount).encodeABI(),
        "from": fromAddress,
        "to": toAddress,
        "gas": web3.utils.toHex(estimateGas * 1.10),
        "gasLimit": web3.utils.toHex(estimateGas * 1.10),
        "gasPrice": web3.utils.toHex(Math.trunc(currentGasPrices.medium * 1e9)),
        "chainId": web3.utils.toHex(chainList.mainnet)
    };
    // Creates an account object from a private key.
    const senderAccount = web3.eth.accounts.privateKeyToAccount(privateKey);
    /**
    * This is where the transaction is authorized on your behalf.
    * The private key is what unlocks your wallet.
    */
    const signedTransaction = await senderAccount.signTransaction(transaction);
    console.log({
        transaction: transaction,
        amount: amount,
        tokenAmount: tokenAmount,
        avgGasPrice: avgGasPrice,
        signedTransaction: signedTransaction
    });

    // We're ready! Submit the raw transaction details to the provider configured above.
    try {
        const receipt = await web3.eth.sendSignedTransaction(signedTransaction.rawTransaction);

        console.log({
            receipt: receipt
        });
        
    } catch (error) {
        console.log({
            error: error.message
        });
    }
}