formToRackParams(form: HTMLFormElement | FormData): Object

Converts a <Form>'s parameters to an object using the same logic as Rack.

This is mainly intended for testing JavaScript components that generate HTML forms to be submitted to Rails.

<form>
  <input type="hidden" name="foo[bar][][id]" value="1" />
  <input type="hidden" name="foo[bar][][id]" value="2" />
</form>

import formToRackParams from '@citizensadvice/form-to-rack-params';

const form = document.querySelector('form');
formToRakeParams(form);

/* =>
  foo: {
    bar: [
      { id: '1' },
      { id: '2' },
    ],
  }
*/