How Can I Handle Asynchronous AJAX Call Return Values?

Asynchronous AJAX Calls and Variable Return

In asynchronous programming, such as with AJAX calls, the variable being returned from the function is not immediately available as the call itself is not executed immediately. In the case of AJAX calls, the call is made asynchronously, meaning it executes in the background while the rest of the code continues to run.

The issue you are facing is that the get_data function in the provided code tries to return the result of the AJAX call directly. However, as the call is asynchronous, the function cannot wait for the result before it returns.

Solution: Using Callbacks

To solve this issue, the get_data function should be modified to use a callback function. A callback function is a function that is passed to another function as an argument and is executed later, after the first function has completed.

In the revised code:

function get_data(data, destination, callback) {
  if (lock_get == 0) {
    lock_get = 1;
    $.ajax({
      type: "POST",
      url: destination,
      async: true,
      data: data,
      success: function(data) {
        lock_get = 0;
        if (data && callback) {
          callback(data);
        }
      }
    });
  }
}

• The get_data function now accepts an additional parameter, callback, which is a function that will be executed after the AJAX call has completed.
• Inside the success callback, the callback function is called with the result of the AJAX call as an argument.

To call the get_data function with a callback:

get_data(data, destination, function(test) {
  notice(test);
});

In this example, an anonymous callback function is used to handle the result of the AJAX call. The result of the call will be passed to the notice function.

By using a callback, the get_data function can initiate the AJAX call and return immediately, while the callback function will be executed later when the result is available.

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