json-form-data

json-form-data

A library to convert JavasScript objects into FormData.

Features

• Supports CommonJS and AMD module loaders
• Converts nested objects and arrays
• Compatible with legacy web browsers
• Supports all primitive data types
• Supports File and FileList data types
• Skips null and undefined values
• Good unit test coverage

Overview

This library converts a JSON object into FormData, allowing files and primitive data to be sent to a server in a single HTTP request.

Single Page Web Applications (SPA's) primarily use JSON formatted payloads. This causes problems when you need to send a file along with additional data, as files cannot be sent to a server in a JSON formatted payload.

This library addresses the limitations of similar libraries by allowing conversion of deeply nested JSON objects, better unit test coverage and exclusion of null and undefined values from the resulting FormData.

Example

Input as JSON

var testObject = {
    prop1: 'test',
    prop2: 2,
    prop3: null,
    prop4: undefined,
    prop5: true,
    prop6: false,
    prop7: new File(['file content'], 'my_file.txt'),
    prop8: {
        prop1: 'test',
        prop2: 2,
        prop3: null,
        prop4: undefined,
        prop5: true,
        prop6: false,
        prop7: [
            'test', 
            2, 
            null, 
            undefined, 
            true, 
            false
        ]
    }
};

var formData = window.jsonToFormData(testObject);

Output as multipart/formdata

prop1
test

prop2
2

prop5
1

prop6
0

prop7
Content-Disposition: form-data; name="My File"; filename="my_file.txt"
Content-Type: text/plain

prop8[prop1]
test

prop8[prop2]
2

prop8[prop5]
1

prop8[prop6]
0

prop8[prop7][0]
test

prop8[prop7][1]
2

prop8[prop7][2]
1

prop8[prop7][3]
0

Browser Support

IE / Edge	Firefox	Chrome	Safari
IE10, IE11, Edge	latest	latest	latest

Sponsors

We use BrowserStack to automate our regression tests to ensure compatibility with supported browsers.