Show unattached images in media loader via javascript/filter

I would like to be able to only show unattached images when calling the media loader via javascript. Here is how I am currently setting it up:

var custom_uploader = wp.media({
    title: 'Assign/Upload Listing Image',
    library: { type: 'image' },
    button: { text: 'Assign Image' },
    multiple: false
  });

I had thought maybe I could use the ‘media_view_settings’ filter, but have been unable to get that to work. I thought I might be able to use something like post_parent=>0, but no joy.

Any help, or just a nudge in the right direction, would be greatly appreciated.