Sending IOTA transaction in more granular way: API calls Prepare_transfer() and Send_transfer()

IOTA101_07CFD43B146C.js

// The snippet is a part of the IOTA Developer Essentials project. You can reach it at https://hribek25.github.io/IOTA101/
// Complete description and story behind the snippet is available at: https://hribek25.github.io/IOTA101/Allchapters_javascript.ipynb.html#07CFD43B146C
// Requirement: A core module of IOTA Javascript Library (!npm install @iota/core)

var iotalib = require('@iota/core');

var NodeURL = "https://nodes.thetangle.org:443";

var iota = iotalib.composeAPI({
    'provider': NodeURL
});

var MySeed = "HGW9HB9LJPYUGVHNGCPLFKKPNZAIIFHZBDHKSGMQKFMANUBASSMSV9TAJSSMPRZZU9SFZULXKJ9YLAIUA";
var TargetAddress1 = "CXDUYK9XGHC9DTSPDMKGGGXAIARSRVAFGHJOCDDHWADLVBBOEHLICHTMGKVDOGRU9TBESJNHAXYPVJ9R9";
var TargetAddress2 = "CYJV9DRIE9NCQJYLOYOJOGKQGOOELTWXVWUYGQSWCNODHJAHACADUAAHQ9ODUICCESOIVZABA9LTMM9RW";

var NowIs = new Date() //get a actual date & time - just to have some meaningfull info

// preparing transactions
var pt = {
    'address': TargetAddress1, //81 trytes long address
    'value': 0, //zero transaction - only data in the message field will be sent
    'message': Converter.asciiToTrytes('Here comes a first message. Now is ' + NowIs), //data needs to be encoded in trytes
    'tag': 'HRIBEK999IOTA999TUTORIAL' //Up to 27 trytes
}

var pt2 = {
    'address': TargetAddress2, //81 trytes long address
    'value': 0, //zero transaction - only data in the message field will be sent
    'message': Converter.asciiToTrytes('Here comes a second message. Now is ' + NowIs), //data needs to be encoded in trytes
    'tag': 'HRIBEK999IOTA999TUTORIAL' //Up to 27 trytes
}

var transfers = [pt,pt2]; // a list of transactions to be sent
var depth = 3;
var minWeightMagnitude = 14;

console.log("Preparing/Broadcasting... Wait please...");

var promise = iota.prepareTransfers(MySeed, transfers) //prepare a bundle in trytes
                            .then(trytes => {                                
                                console.log("Almost prepared bundle - tips and POW are still missing");
                                console.log(trytes);
                                console.log("Searching for tips and performing POW... Wait please...");
                                return iota.sendTrytes(trytes, depth, minWeightMagnitude); //perform GTTA + POW + BROADCASTING
                            })
                            .then(bundle => {
                                console.log("Bundle was broadcasted.");
                                console.log("Final transactions were returned - including nonce (POW)");
                                bundle.map(tx => console.log(tx))
                            })
                            .catch(err => {
                                console.log("Something went wrong: %s", err);
                            })