emulating the behavior of a synchronous XmlHttpRequest

Question

emulating the behavior of a synchronous XmlHttpRequest

While I have taken the time to explore similar questions like Pattern for wrapping an Asynchronous JavaScript function to make it synchronous & Make async event synchronous in JavaScript, I want to ensure that I consider all potential solutions.

Is it feasible to "transform" an asynchronous XmlHttpRequest into a pseudo-synchronous one by utilizing setInterval or setTimeout? My thought is that, upon successful completion of the Ajax request, a variable could be set to trigger a while loop (which has invoked either setInterval or setTimeout) along with a corresponding callback function to terminate. Am I misinterpreting the capabilities and limitations of setInterval and/or setTimeout?

javascript ajax settimeout synchronous setinterval

Answer 1

Answer №1

Avoid using setInterval and setTimeout as described in your approach. Instead, focus on utilizing nested functions to write code in a more synchronous manner.

For instance:

XHR.get(your_data, function()
   {
      // Write your code synchronously here
   });

While you may use setInterval and/or setTimeout for polling a success code, it is not recommended. This method has drawbacks such as increased latency, high CPU usage, and limited scalability with multiple XHR requests.

XHR will execute your function upon completion, therefore repeatedly checking "Are we done yet?" is unnecessary. However, if there is specific behavior that needs to wait for the response (like an animation dependent on the data), you can include blocking code within an if statement:

var tick = window.setTimeout(tock, 20);
var tock = function()
{
   if (response_done)
   {
      // Execute dependent code
   }
   tick = window.setTimeout(tock, 20);
}
XHR.get(your_data, function() { /*Handle response*/ response_done = true; });

Answer 2

Avoid using setInterval and setTimeout as described in your approach. Instead, focus on utilizing nested functions to write code in a more synchronous manner.

For instance:

XHR.get(your_data, function()
   {
      // Write your code synchronously here
   });

While you may use setInterval and/or setTimeout for polling a success code, it is not recommended. This method has drawbacks such as increased latency, high CPU usage, and limited scalability with multiple XHR requests.

XHR will execute your function upon completion, therefore repeatedly checking "Are we done yet?" is unnecessary. However, if there is specific behavior that needs to wait for the response (like an animation dependent on the data), you can include blocking code within an if statement:

var tick = window.setTimeout(tock, 20);
var tock = function()
{
   if (response_done)
   {
      // Execute dependent code
   }
   tick = window.setTimeout(tock, 20);
}
XHR.get(your_data, function() { /*Handle response*/ response_done = true; });

Answer 3

Answer №2

Understanding your query, you can create a similar outcome by implementing the code below:

var updateInterval =
    window.setInterval(function() {
        // perform an update cycle, simulating a while loop
    }, 100);

$.get('http://example.com/areWeThereYet', function() {
    // stop the intervals (simulation of the loop)
    window.clearInterval(updateInterval);
});

Answer 4

Understanding your query, you can create a similar outcome by implementing the code below:

var updateInterval =
    window.setInterval(function() {
        // perform an update cycle, simulating a while loop
    }, 100);

$.get('http://example.com/areWeThereYet', function() {
    // stop the intervals (simulation of the loop)
    window.clearInterval(updateInterval);
});

emulating the behavior of a synchronous XmlHttpRequest

Answer №1

Answer №2

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