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

问题

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();
            }
        });

回答1:

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});

回答2:

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.

回答3:

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);
...

回答4:

Function:

function appendArray(form_data, values, name){
    if(!values && name)
        form_data.append(name, '');
    else{
        if(typeof values == 'object'){
            for(key in values){
                if(typeof values[key] == 'object')
                    appendArray(form_data, values[key], name + '[' + key + ']');
                else
                    form_data.append(name + '[' + key + ']', values[key]);
            }
        }else
            form_data.append(name, values);
    }

    return form_data;
}

Use:

var form = document.createElement('form');// or document.getElementById('my_form_id');
var formdata = new FormData(form);

appendArray(formdata, {
    'sefgusyg': {
        'sujyfgsujyfsg': 'srkisgfisfsgsrg'
    }, test1: 5, test2: 6, test3: 8, test4: 3, test5: [
        'sejyfgjy',
        'isdyfgusygf'
    ]
});

回答5:

This works for me when I sent file + text + array:

const uploadData = new FormData();
if (isArray(value)) {
  const k = `${key}[]`;
  uploadData.append(k, value);
} else {
  uploadData.append(key, value);
}


const headers = {
  'Content-Type': 'multipart/form-data',
};

回答6:

var formData = new FormData;
var alphaArray = ['A', 'B', 'C','D','E'];
for (var i = 0; i < alphaArray.length; i++) {
    formData.append('listOfAlphabet', alphaArray [i]);
}

And In your request you will get array of alphabets.

回答7:

You can only stringify the array and append it. Sends the array as an actual Array even if it has only one item.

const array = [ 1, 2 ];
let formData = new FormData();
formData.append("numbers", JSON.stringify(array));

回答8:

Simply you can do like this:

var formData = new FormData();
formData.append('array[key1]', this.array.key1);
formData.append('array[key2]', this.array.key2);

来源：https://stackoverflow.com/questions/14026539/can-i-append-an-array-to-formdata-in-javascript