Stellar JS SDK create account and set trust-line

create_and_trust.js

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


// an arbitary list of trusted assets
const ASSETS = {
    'XPORT': new StellarSdk.Asset('XPORT', 'GCC4HAL7SOR7AZBF53SUTVAJT4OHYLBHOUJMM3IAF5YLFF7OVVAWLVFT'),
    'USDT': new StellarSdk.Asset('USDT', 'GCQTGZQQ5G4PTM2GL7CDIFKUBIPEC52BROAQIAPW53XBRJVN6ZJVTG6V'),
    'MOBI' : new StellarSdk.Asset('MOBI', 'GA6HCMBLTZS5VYYBCATRBRZ3BZJMAFUDKYYF6AH6MVCMGWMRDNSWJPIH'),
    'XLM': StellarSdk.Asset.native()
}

// helper function to get desired asset object
const getAsset = (asset) => {
    if (ASSETS[asset]) return ASSETS[asset]
    return StellarSdk.Asset.native()
}


const options = {
    starting_secret : 'S ...',
    to_be_created_secret : 'S ...',
    asset_code: 'XPORT'
}

const createAndTrust = (options) => {
    
    const starting_keypair = StellarSdk.Keypair.fromSecret(options.starting_secret);
    const to_be_created_keypair = StellarSdk.Keypair.fromSecret(options.to_be_created_secret)
    
    // this transaction may or may not (see if condition below) have multiple signers
    // it will certainly have the 'starting_keypair' as signer, so initalise an array with 'starting_keypair' included
    const signers = [starting_keypair] 
    
    return server.loadAccount(starting_keypair.publicKey())
    .then(
        account => {
            
            const transaction = new StellarSdk.TransactionBuilder(account);
            
            transaction.addOperation(
                StellarSdk.Operation.createAccount({
                    destination: 'G ...',
                    startingBalance: '2' // xlm
                })
            );
            
            if (options.asset_code != 'XLM') { // no need to set trust for XLM ...
                transaction.addOperation(
                    StellarSdk.Operation.changeTrust({
                        asset: getAsset(options.asset_code), // note: getAsset returns an Asset object with issuing Code+PK
                        source: to_be_created_keypair.publicKey() // note: the new account is the 'source' of this operation, it will have to be included in the transactions signers
                    })
                )
                signers.push(to_be_created_keypair) // add second signer to list of signers
            }
            
            const tx = transaction.build()
            tx.sign(...signers) // expand signers array to pass each signer as an arg
            
            return server.submitTransaction(tx)
            .then(
                res => { console.log('Success! Account Created.') },
                err => { throw err }
            )
        }
    );
}

createAndTrust(options)