Nodejs, How do I wait until the previous post request is completed.
Below is the Snippet:

```
var data ="xxxx"
let XMLHttpRequest1 = require("xmlhttprequest").XMLHttpRequest;
var xhr = new XMLHttpRequest1();
xhr.withCredentials = true;
xhr.open("POST", https://corpqa.sts.xxxx.com/adfs/oauth2/token);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.send(data);
console.log("Execution Order 1");
xhr.addEventListener("readystatechange",  function() {
  if(this.readyState === 4) {
    console.log("Execution Order 2");
    //console.log(this.responseText);

  }
});
console.log("Execution Order 3");

```

In NodeJS, below is the Output of the above code:

```
Execution Order 1
Execution Order 3
Execution Order 2

```

How do I make code to WAIT for response, execute this.readyState ===4. before it proceed to execute console.log("Execution Order 3").

Expected Output

```
Execution Order 1
Execution Order 2
Execution Order 3

```