Basic Examples  [JS Stellar SDK]

• Creating a payment Transaction
• Loading an account’s transaction history
• Streaming payment events

Creating a payment transaction

js-stellar-sdk exposes the TransactionBuilder class from js-stellar-base. There are more examples of building transactions here. All those examples can be signed and submitted to Stellar in a similar manner as is done below.

In this example you must ensure that the destination account exists

// Create, sign, and submit a transaction using JS Stellar SDK.

// Assumes that you have the following items:
// 1. Secret key of a funded account to be the source account
// 2. Public key of an existing account as a recipient
//    These two keys can be created and funded by the friendbot at
//    https://www.stellar.org/laboratory/ under the heading "Quick Start: Test Account"
// 3. Access to JS Stellar SDK (https://github.com/stellar/js-stellar-sdk)
//    either through Node.js or in the browser.

// This code can be run in the browser at https://www.stellar.org/laboratory/
// That site exposes a global StellarSdk object you can use.
// To run this code in the Chrome, open the console tab in the DevTools.
// The hotkey to open the DevTools console is Ctrl+Shift+J or (Cmd+Opt+J on Mac).

// To use in node, do `npm install stellar-sdk` and uncomment the following line.
// var StellarSdk = require('stellar-sdk');

// The source account is the account we will be signing and sending from.
var sourceSecretKey = 'SAKRB7EE6H23EF733WFU76RPIYOPEWVOMBBUXDQYQ3OF4NF6ZY6B6VLW';

// Derive Keypair object and public key (that starts with a G) from the secret
var sourceKeypair = StellarSdk.Keypair.fromSecret(sourceSecretKey);
var sourcePublicKey = sourceKeypair.publicKey();

var receiverPublicKey = 'GAIRISXKPLOWZBMFRPU5XRGUUX3VMA3ZEWKBM5MSNRU3CHV6P4PYZ74D';

// Configure StellarSdk to talk to the horizon instance hosted by Stellar.org
// To use the live network, set the hostname to 'horizon.stellar.org'
var server = new StellarSdk.Server('https://horizon-testnet.stellar.org');

// Uncomment the following line to build transactions for the live network. Be
// sure to also change the horizon hostname.
// StellarSdk.Network.usePublicNetwork();
StellarSdk.Network.useTestNetwork();

// Transactions require a valid sequence number that is specific to this account.
// We can fetch the current sequence number for the source account from Horizon.
server.loadAccount(sourcePublicKey)
  .then(function(account) {
    var transaction = new StellarSdk.TransactionBuilder(account)
      // Add a payment operation to the transaction
      .addOperation(StellarSdk.Operation.payment({
        destination: receiverPublicKey,
        // The term native asset refers to lumens
        asset: StellarSdk.Asset.native(),
        // Specify 350.1234567 lumens. Lumens are divisible to seven digits past
        // the decimal. They are represented in JS Stellar SDK in string format
        // to avoid errors from the use of the JavaScript Number data structure.
        amount: '350.1234567',
      }))
      // Uncomment to add a memo (https://www.stellar.org/developers/learn/concepts/transactions.html)
      // .addMemo(StellarSdk.Memo.text('Hello world!'))
      .build();

    // Sign this transaction with the secret key
    // NOTE: signing is transaction is network specific. Test network transactions
    // won't work in the public network. To switch networks, use the Network object
    // as explained above (look for StellarSdk.Network).
    transaction.sign(sourceKeypair);

    // Let's see the XDR (encoded in base64) of the transaction we just built
    console.log(transaction.toEnvelope().toXDR('base64'));

    // Submit the transaction to the Horizon server. The Horizon server will then
    // submit the transaction into the network for us.
    server.submitTransaction(transaction)
      .then(function(transactionResult) {
        console.log(JSON.stringify(transactionResult, null, 2));
        console.log('\nSuccess! View the transaction at: ');
        console.log(transactionResult._links.transaction.href);
      })
      .catch(function(err) {
        console.log('An error has occured:');
        console.log(err);
      });
  })
  .catch(function(e) {
    console.error(e);
  });

Loading an account’s transaction history

Let’s say you want to look at an account’s transaction history. You can use the transactions() command and pass in the account address to forAccount as the resource you’re interested in.

var StellarSdk = require('stellar-sdk')
var server = new StellarSdk.Server('https://horizon-testnet.stellar.org');
var accountId = 'GBBORXCY3PQRRDLJ7G7DWHQBXPCJVFGJ4RGMJQVAX6ORAUH6RWSPP6FM';

server.transactions()
    .forAccount(accountId)
    .call()
    .then(function (page) {
        console.log('Page 1: ');
        console.log(page.records);
        return page.next();
    })
    .then(function (page) {
        console.log('Page 2: ');
        console.log(page.records);
    })
    .catch(function (err) {
        console.log(err);
    });

Streaming payment events

js-stellar-sdk provides streaming support for Horizon endpoints using EventSource. You can pass a function to handle any events that occur on the stream.

Try submitting a transaction (via the guide above) while running the following code example.

var StellarSdk = require('stellar-sdk')
var server = new StellarSdk.Server('https://horizon-testnet.stellar.org');

// Get a message any time a payment occurs. Cursor is set to "now" to be notified
// of payments happening starting from when this script runs (as opposed to from
// the beginning of time).
var es = server.payments()
  .cursor('now')
  .stream({
    onmessage: function (message) {
      console.log(message);
    }
  })

For more on streaming events, please check out the Horizon responses documentation and this guide to server-sent events.