Error: XDR Write Error: not an integer while issuing the asset in stellar network

Question

I am trying to issue an asset in stellar using the following code

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

// Keys for accounts to issue and receive the new asset
var issuingKeys = StellarSdk.Keypair.fromSecret('SB3VKUYOWTOZKN3IUTLKE4IMEDEMPVPY6ZRQTPP74XZKRxxxNCIKExxx');
//console.log(issuingKeys);

var receivingKeys = StellarSdk.Keypair.fromSecret('SB3Q65ARACYPDK5FxxxLG2KPPFZT7R3SVPPBQAPW6FC75XNxxx3LNLGB');

// Create an object to represent the new asset
var astroDollar = new StellarSdk.Asset('AstroDollar', issuingKeys.publicKey());

// First, the receiving account must trust the asset
server.loadAccount(receivingKeys.publicKey())
  .then(function(receiver) {
    const fee =  server.fetchBaseFee();

    var transaction = new StellarSdk.TransactionBuilder(receiver,   {fee} )
      // The `changeTrust` operation creates (or alters) a trustline
      // The `limit` parameter below is optional
      .addOperation(StellarSdk.Operation.changeTrust({
        asset: astroDollar,
        limit: '1000'
      }))
      .setTimeout(30)
      .build();
    transaction.sign(receivingKeys);
    return server.submitTransaction(transaction);
  });

But I'm getting the following error (node:9922) UnhandledPromiseRejectionWarning: Error: XDR Write Error: not an integer, Can anyone tell me how to resolve this issue?

Answer 1

fetchBaseFee is a promise, you have to await it.

const fee =  await server.fetchBaseFee();