form state array values are missing values

I am not sure the best way to work with form values so i tend to approach it as i would with Drupal's php forms; but that doesn't work within Drupalgap afaik.

i have a routine which adds nids to an array for storage into local storage. without putting too much thought into it i store a simple array like this:

nids = [34, 45, 64];
variable_set('nids', nids); 

i later want to use this list as options for a checkboxes form element and i set this up as this:

function mynids_form(form, form_state) {
  
  var nids = variable_get('nids', {});
 // need to convert the json string that getts stored in local storage 
 if (nids.length) {
    nids = JSON.parse(nids);
  }
  nids = $.extend({}, nids);
  form.elements['my-nids'] = {
    title: 'My NIDs',
    type: 'checkboxes',
    options: nids
  };
  form.elements['submit'] = {
    type: 'submit',
    value: 'Remove from NIDs'
  };
  
  return (form);
}

although a bit of a pita to deal with the json string, this generally seems to work and i now get a set of checkboxes with the labels:

34
45
64

but, when i submit this form, the values in form_state['values']['my-nids'] loses the checkbox values and i only retain the keys:

0:0
1:0
2:0

if i jump through a few more hoops when i am storing the array and store as an associated array (object) so i am storing this:
{34:34, 45:45, 64:64}

then when i submit my form i get this for form_state['values']['my-nids']:

34:0
45:0
64:0

so, i guess i could now do an array_keys (whatever js equivalent is) to get the key values; but this seems like much more work than it needs to be.