StellarRequire.js

const stellarSdk = require("stellar-sdk")
stellarSdk.Network.useTestNetwork()
const blockchain = new stellarSdk.Server("https://horizon-testnet.stellar.org")

// get private key from https://portal.willet.io/
const serverKeyPair = stellarSdk.Keypair.fromSecret("SB3KVB6RN5MOJJUZFLRDZNWN67PZV6IF6L74PMSHJEXHX2ABVSJUZDVA")

// get server account info
const serverAccount = await blockchain.loadAccount(serverKeyPair.publicKey())

// create a completely new and unique pair of keys
const escrowKeyPair = stellarSdk.Keypair.random()

// https://www.stellar.org/developers/js-stellar-base/reference/base-examples.html#creating-an-account
const transaction = new stellarSdk.TransactionBuilder(serverAccount)
.addOperation(
  stellarSdk.Operation.createAccount({ 
    destination: escrowKeyPair.publicKey(), // create escrow account
    startingBalance: '2.00001' // 1 base + 0.5[base_reserve] per op(2) + tx fee (0.00001) => 2.00001 XLM minimum
  })
)
.addOperation(
  stellarSdk.Operation.setOptions({
    source: escrowKeyPair.publicKey(),   
    signer: {
      ed25519PublicKey: serverKeyPair.publicKey(), // add server as signer on escrow account
      weight: 1
    }
  })
)
.build()

// sign transaction
transaction.sign(serverKeyPair, escrowKeyPair)

// broadcast transaction
await blockchain.submitTransaction(transaction)