Can I append an array to 'formdata' in javascript?

I'm using FormData to upload files. I also want to send an array of other data.

When I send just the image, it works fine. When I append some text to the formdata, it works fine. When I try to attach the 'tags' array below, everything else works fine but no array is sent.

Any known issues with FormData and appending arrays?

Instantiate formData:

formdata = new FormData();

The array I create. Console.log shows everything working fine.

        // Get the tags
        tags = new Array();
        $('.tag-form').each(function(i){
            article = $(this).find('input[name="article"]').val();
            gender = $(this).find('input[name="gender"]').val();
            brand = $(this).find('input[name="brand"]').val();
            this_tag = new Array();
            this_tag.article = article;
            this_tag.gender = gender;
            this_tag.brand = brand;
            tags.push(this_tag);    
            console.log('This is tags array: ');
            console.log(tags);
        });
        formdata.append('tags', tags);
        console.log('This is formdata: ');
        console.log(formdata);

How I send it:

        // Send to server
        $.ajax({
            url: "../../build/ajaxes/upload-photo.php",
            type: "POST",
            data: formdata,
            processData: false,
            contentType: false,
            success: function (response) {
                console.log(response);
                $.fancybox.close();
            }
        });

How about this?

formdata.append('tags', JSON.stringify(tags));

... and, correspondingly, using json_decode on server to deparse it. See, the second value of FormData.append can be...

a Blob, File, or a string, if neither, the value is converted to a string

The way I see it, your tags array contains objects (@Musa is right, btw; making this_tag an Array, then assigning string properties to it makes no sense; use plain object instead), so native conversion (with toString()) won't be enough. JSON'ing should get the info through, though.

As a sidenote, I'd rewrite the property assigning block just into this:

tags.push({article: article, gender: gender, brand: brand});

Writing as

var formData = new FormData;
var array = ['1', '2'];
for (var i = 0; i < array.length; i++) {
    formData.append('array_php_side[]', array[i]);
}

you can receive just as normal array post/get by php.

use "xxx[]" as name of the field in formdata (you will get an array of - stringified objects - in you case)

so within your loop

$('.tag-form').each(function(i){
            article = $(this).find('input[name="article"]').val();
            gender = $(this).find('input[name="gender"]').val();
            brand = $(this).find('input[name="brand"]').val();
            this_tag = new Array();
            this_tag.article = article;
            this_tag.gender = gender;
            this_tag.brand = brand;
            //tags.push(this_tag);    
            formdata.append('tags[]', this_tag);
...

We can simply do like this.

formData = new FormData;
words = ["apple", "ball", "cat"]
words.forEach((item) => formData.append("words[]", item))

// verify the data
console.log(formData.getAll("words[]"))
//["apple", "ball", "cat"]

On server-side you will get words = ["apple", "ball", "cat"]