How to add a Library as a dependencies in another Library? I'm building D3 libraries to visualize data. The visualizations require the topojson Javascript library to manipulate geo shapes. 

I want to include the topojson javascript library as a dependency in my custom libraries and right now I'm simply including it in the .info file for the each library:

files[js][] = 'js/topojson.v0.min.js'

However, this adds the topojson file to &lt;head&gt; section of the page more than once when I have several of these includes.

I want to be able to load the file once and use it in anyone of my D3 libraries. How do I do that?
You can add another dependency by using custom module 

function hook_library() {
  // Library One.
  $libraries['library-1'] = array(
    'title' =&gt; 'Library One',
    'website' =&gt; 'http://example.com/library-1',
    'version' =&gt; '1.2',
    'js' =&gt; array(
      drupal_get_path('module', 'my_module') . '/library-1.js' =&gt; array(),
    ),
    'css' =&gt; array(
      drupal_get_path('module', 'my_module') . '/library-2.css' =&gt; array(
        'type' =&gt; 'file',
        'media' =&gt; 'screen',
      ),
    ),
  );
  // Library Two.
  $libraries['library-2'] = array(
    'title' =&gt; 'Library Two',
    'website' =&gt; 'http://example.com/library-2',
    'version' =&gt; '3.1-beta1',
    'js' =&gt; array(
      // JavaScript settings may use the 'data' key.
      array(
        'type' =&gt; 'setting',
        'data' =&gt; array('library2' =&gt; TRUE),
      ),
    ),
    'dependencies' =&gt; array(
      // Require jQuery UI core by System module.
      array('system', 'ui'),
      // Require our other library.
      array('my_module', 'library-1'),
      // Require another library.
      array('other_module', 'library-3'),
    ),
  );
  return $libraries;
}