The setAccount() method is called by the AppLogin component. Depending on whether the user clicks on Acme Inc or Apex Corp, the input parameter, 1 or 2, is sent to the method.

If the value of the input parameter is 2, indicating the customer is Apex Corp (a Bank B customer), the server state variable is set to localhost:8001, which is the listening port of the backend server of Bank B, as shown in the following code block:

if (flag == 2)
 {
 server = 'localhost:8001' 
 };

Next, we fetch the customer's details from the backend server. We make a fetch call to the /customerinfo API endpoint, like this:

var url = 'http://'+ server +'/customerinfo';
 fetch(url, {
 method: 'POST',
 headers: {
 'Accept': 'application/json',
 'Content-Type': 'application/json',
 }, 
 body: JSON.stringify({
 userId : app.state.userId 
 }) 
 }).then(function(response,error){

• On the response from the backend server, we parse the response object for the customer's name, account, address, and current balance. We set these values to the app state.
• Additionally, a bank variable is also added to the app state. The bank variable is to Bank A or Bank B, depending on whether the input parameter to the setAccount() method was 1 or 2. We also add the server variable with the listening port of the bank backend server, as follows:

then(function(data){
 
 var bank;
 
if(flag == 1)
 {
 bank = 'Bank A';
 }
 else
 {
 bank = 'Bank B';
 } 
 
 app.setState({
 name: data.name,
 account: data.account,
 balance: data.balance,
 address: data.address,
 bank: bank,
 server: server
 });

Next, let's look at the view setters for the app.