appending array to FormData and send via AJAX

📝Tech Tips: How to Append an Array to FormData and Send via AJAX 🚀

Are you struggling with appending an array to FormData and sending it via AJAX? 🤔 Don't worry, you're not alone! Many developers face this challenge when trying to submit multipart forms with arrays, text fields, and files seamlessly. 😓

In this blog post, we'll address this common issue and provide easy solutions to help you achieve your desired result. 💡 So, let's dive in and find out how to solve this problem! 💪

The Context 📚

Let's start by understanding the context in which this problem arises. Below is an example of how the data is being appended to the FormData object and sent via AJAX:

var attachments = document.getElementById('files');
var data = new FormData();

for (var i = 0; i < attachments.files.length; i++) {
    data.append('file', attachments.files[i]);
    console.log(attachments.files[i]);

    data.append('headline', headline);
    data.append('article', article);
    data.append('arr', arr);
    data.append('tag', tag);
}

$.ajax({
    type: "post",
    url: 'php/submittionform.php',
    cache: false,
    processData: false,
    contentType: false,
    data: data,
    success: function(request) {
        $('#box').html(request);
    }
});

The Issue 😫

The problem occurs on the PHP side when the arr variable, which is initially an array, appears as a string. This happens when the data is sent via AJAX using FormData. 🤯

Interestingly, if you send the data using the simple $.POST option instead of FormData, the arr variable arrives correctly as an array on the PHP side. However, this approach doesn't allow you to send files simultaneously. 😢

The Solutions 🚀

Solution 1: JSON.stringify

One easy solution is to JSON.stringify the array before appending it to FormData:

data.append('arr', JSON.stringify(arr));

And on the PHP side, you can use json_decode to convert the received string back to an array:

$arr = json_decode($_POST['arr'], true);

Solution 2: Converting the Array to Multiple FormData Instances

Another workaround is to convert the array into multiple instances of FormData. You can append each element of the array individually to a separate FormData instance, and then append all the instances to another FormData that will be sent via AJAX. The PHP side will handle it as an array accordingly.

for (var i = 0; i < arr.length; i++) {
    var tempData = new FormData();
    tempData.append('arr', arr[i]);
    data.append('arr[]', tempData.get('arr'));
}

On the PHP side, you can retrieve the array as follows:

$arr = $_POST['arr'];

The Call-to-Action 📣

Now that you have learned how to overcome the hurdles of appending an array to FormData and sending it via AJAX, it's time to put this knowledge into action! ✨

Try implementing the provided solutions and see which one works best for your specific use case. Don't forget to share your experiences and tips with the community! 💬

If you have any other questions or need further assistance, feel free to leave a comment below or reach out to us. We're here to help! 🤝

Happy coding! 💻🚀

Do you have any other tech-related questions or challenges? Let us know in the comments! 👇