Send bitcoin transaction to multiple addresses

bitcoin_transaction.js

/**
 * package.json

  "devDependencies": {
    "bitcore-lib": "^0.13.18",
    "async": "0.9.0",
    "request": "2.53.0"
  }
*/

var bitcore = require("bitcore-lib");
var fs = require("fs");
var request = require('request');
var Async = require("async");

/** END EXAMPLE INPUT, YOU SHOULD MODIFY TO YOUR CASE **/
// Your public key
var from_public = "your_public_key_here";
// Your private key
var private_key = 'your_private_key_here';

// Define which addresses you wan to send, just 1 item or more, below are 2 example addresses
var send_addresses = [
    //adress and amount in satoshies
    { address: "1Hyxrc88gd6s9w1MpVz3e1NLf4FTZxBby6", amount: 327880 },//approximate 2$
    { address: "19tqEocN86Y4rHyeB2G4ezUpYNxv94sdmM", amount: 163940 }, //approximate 1$
];


/** END EXAMPLE INPUT, YOU SHOULD MODIFY TO YOUR CASE **/


const push_bitcoin_url = "https://blockchain.info/pushtx";
const check_address_url = "https://api.blockcypher.com/v1/btc/main/addrs/{address}?unspentOnly=1";
//According https://api.blockcypher.com/v1/btc/main
const fee_per_kb = 71050; // 71050 satoshies 0.43$/kb fee
const min_transaction_amount = 546; // request dust is 546 satoshies

Async.waterfall([


    function (callback) {

        var check_url = check_address_url.replace('{address}', from_public);
        console.log("check_url", check_url);

        request(check_url, function (error, response, body) {
            if (!error && response.statusCode == 200) {
                //console.log(body);
                var json = JSON.parse(body);

                var unspend_transactions = [];

                if (json.unconfirmed_txrefs) {
                    for (var i = 0; i < json.unconfirmed_txrefs.length; i++) {
                        var item = json.unconfirmed_txrefs[i];

                        if (!item.double_spend) {
                            //if there is unconfirmation transaction but there is my public address here
                            if (item.address == from_public) {
                                unspend_transactions.push(item);
                            }
                        }
                        else {
                            console.log("detected double spend on unconfirmation transactions");
                        }
                    }
                }

                if (json.txrefs) {
                    for (var i = 0; i < json.txrefs.length; i++) {
                        var item = json.txrefs[i];

                        if (!item.double_spend) {
                            unspend_transactions.push(item);

                        } else {
                            console.log("detected double spend on confirmed transactions");
                        }
                    }
                }

                callback(null, unspend_transactions);

            } else {
                callback("can not get input address information");
            }
        })

    },
    function (input_transactions, callback) {


        //console.log("input_transactions",input_transactions);


        var script = new bitcore.Script(new bitcore.Address(from_public)).toHex();

        var privateKey = new bitcore.PrivateKey(private_key);

        var total_value = 0;

        var transaction = new bitcore.Transaction();

        for (var i = 0; i < input_transactions.length; i++) {
            var item = input_transactions[i];
            var utxo = {
                "txId": item.tx_hash,
                "outputIndex": item.tx_output_n,
                "address": from_public,
                "script": script,
                "satoshis": item.value
            };

            total_value += item.value;

            transaction.from(utxo)

        }

        //Total output amount by satoshies

        var total_output = 0;
        for (var i = 0; i < send_addresses.length; i++) {
            var address_item = send_addresses[i];
            transaction.to(address_item.address, address_item.amount)
            total_output += address_item.amount;
        }

        //  estimate size of transaction and calculate fee
        var fee = Math.floor(fee_per_kb * transaction._estimateSize() / 1024);

        console.log("total_output", total_output);
        console.log("total_value", total_value);
        console.log("fee", fee);

        if (total_value < total_output + fee) {
            return callback("Not enough for create transaction");
        }

        var change_amount = total_value - total_output - fee;

        if (change_amount > 0 && change_amount < min_transaction_amount) {
            return callback("The change amount is too small");
        }

        console.log("change_amount", change_amount);


        transaction.fee(fee);
        if (change_amount > 0) {
            transaction.change(from_public)
        }

        transaction.enableRBF()
            .sign(privateKey);

        var tx_hex = transaction.serialize();

        console.log("tx_hex", tx_hex);

        /*console.log( JSON.stringify(transaction.toObject()), "end");*/



        var post_params = {
            url: push_bitcoin_url, form: { tx: tx_hex }
        };

        request.post(post_params, function (error, response, body) {

            if (!error && response.statusCode == 200) {
                console.log("body", body) // Show the HTML for the Google homepage.
            } else {
                console.log("body", body) // Show the HTML for the Google homepage.
                console.log("statusCode", response.statusCode);
            }

            callback(null);

        });

    }
], function (err, result) {
    console.log('info', "END TASK");

    if (err) {
        console.log('info', err);
    }

    process.exit();
});