Explanation requested for previous response about returning ajax data to the parent function

Question

Explanation requested for previous response about returning ajax data to the parent function

After coming across a helpful answer in the question titled How do I return the response from an asynchronous call?, I attempted to implement it without success.

Reviewing Hemant Bavle's answer (currently with 62 votes) gave me hope, but my implementation is still not working as expected. Below is my code snippet (excluding ajaxSetup() and fail() for brevity):

function isGoodPIN(pin) {
    var result;
    var cURL = "server/checkPIN?pin=" + pin;

    function setResult(ajaxResult) {
        result = ajaxResult; // <--------- true here...
    }

    var ajaxResponse = $.get(cURL, function (data) {
        // data is "OK" here...
        setResult(data == "OK" ? true : false);
    });

    return result; //<--------- undefined here
}

I suspect that there might be a scope issue since the variable result in setResult() is confined within the function. How can this problem be resolved?

javascript jquery ajax

Answer 1

Answer №1

It seems like you may need to revisit the concept of AJAX, specifically understanding that it operates asynchronously. This means that a parent function cannot directly return data from an AJAX request due to the timing of execution.

To address this, consider restructuring your code to utilize callback functions that are triggered by the result of the AJAX call. Here's an example:

function checkPIN(pin, successCallback, errorCallback) {
    $.get('server/validatePIN', { pin: pin }, function (data) {
        if (data === "Valid") {
            successCallback();
        } else { 
            errorCallback();
        }
    })
}

checkPIN('4321', function() {
    console.log('PIN is valid');
}, function() {
    console.log('Invalid PIN');
});

Answer 2

It seems like you may need to revisit the concept of AJAX, specifically understanding that it operates asynchronously. This means that a parent function cannot directly return data from an AJAX request due to the timing of execution.

To address this, consider restructuring your code to utilize callback functions that are triggered by the result of the AJAX call. Here's an example:

function checkPIN(pin, successCallback, errorCallback) {
    $.get('server/validatePIN', { pin: pin }, function (data) {
        if (data === "Valid") {
            successCallback();
        } else { 
            errorCallback();
        }
    })
}

checkPIN('4321', function() {
    console.log('PIN is valid');
}, function() {
    console.log('Invalid PIN');
});

Explanation requested for previous response about returning ajax data to the parent function

Answer №1

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