autonest

A lightweight utility for converting deeply nested data structures to FormData objects and back, preserving the original structure.

Features

• Convert any deeply nested data structure into a FormData object.
• Reconstruct the original nested data structure from a flat key-value object.
• Supports arrays, objects, primitives, dates, and files (File/Blob).
• Handles empty objects, arrays, and special characters in keys.

Installation

npm install autonest

Usage

Importing the functions

import { buildFormData, formDataToNestedObject } from 'autonest';

Converting Data to FormData

const data = {
  user: {
    name: 'Michael',
    age: 24,
    hobbies: ['snowboarding', 'programming'],
    profilePicture: new File([/* file data */], 'profile.jpg', { type: 'image/jpeg' }),
    address: {
      city: 'NYC',
      zip: '10001',
    },
  },
};

const formData = buildFormData(data);

// Send formData via fetch or XMLHttpRequest
fetch('/api/upload', {
  method: 'POST',
  body: formData,
});

Reconstructing the Nested Object from FormData

const reconstructedData = formDataToNestedObject(formData);

console.log(reconstructedData);
// Output:
// {
//   user: {
//     name: 'Michael',
//     age: '24',
//     hobbies: ['snowboarding', 'programming'],
//     profilePicture: File { ... },
//     address: {
//       city: 'NYC',
//       zip: '10001',
//     },
//   },
// }

API

buildFormData(data, formData = new FormData(), parentKey)

Converts a nested data structure into a FormData object.

Parameters

• data (required): The data structure to convert.
• formData (optional): An existing FormData object to append to.
• parentKey (optional): Used internally for recursion.

Returns

A FormData object representing the data.

formDataToNestedObject(formData)

Reconstructs the original nested data structure from a FormData object.

Parameters

• formData (required): The FormData object to convert.

Returns

The reconstructed data structure.

Examples

Handling Files

const data = {
  document: new File([/* file data */], 'doc.pdf', { type: 'application/pdf' }),
};

const formData = buildFormData(data);

// Reconstructing
const reconstructedData = formDataToNestedObject(formData);

console.log(reconstructedData.document); // File object

TESTING

Run tests to ensure everything is working correctly.

npm test

Contributing

Contributions are welcome! Please open an issue or submit a pull request.