How can I return the response from an asynchronous call?

Question

Aryan Kumar · Answer

There are a few different ways to return the response from an asynchronous call. One way is to use a promise. A promise is an object that represents the eventual completion or failure of an asynchronous operation. You can use promises to chain together asynchronous operations and to handle errors.
The following code shows how to return the response from an asynchronous call using a promise:
function getUsers() {
  return new Promise(function(resolve, reject) {
    // Make the asynchronous call.
    var xhr = new XMLHttpRequest();
    xhr.open("GET", "/api/users");
    xhr.onload = function() {
      if (xhr.status === 200) {
        resolve(JSON.parse(xhr.responseText));
      } else {
        reject(new Error(xhr.statusText));
      }
    };
    xhr.send();
  });
}
In this code, the getUsers() function returns a promise. The 
getUsers() function makes an asynchronous call to the /api/users endpoint. The
getUsers() function then resolves the promise with the response data if the call is successful, or rejects the promise with an error if the call is not successful.
Another way to return the response from an asynchronous call is to use an async function. An async function is a function that can be used to perform asynchronous operations. Async functions use promises internally to handle the asynchronous operations.
The following code shows how to return the response from an asynchronous call using an async function:
async function getUsers() {
  // Make the asynchronous call.
  var xhr = new XMLHttpRequest();
  xhr.open("GET", "/api/users");
  xhr.onload = function() {
    if (xhr.status === 200) {
      return JSON.parse(xhr.responseText);
    } else {
      throw new Error(xhr.statusText);
    }
  };
  xhr.send();
}
In this code, the getUsers() function is an async function. The 
getUsers() function makes an asynchronous call to the /api/users endpoint. The
getUsers() function then returns the response data if the call is successful, or throws an error if the call is not successful.

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How can I return the response from an asynchronous call?

Utpal Vishwas

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