How to add_js per content type in my module?
Here's how to add content type specific javascript to a node using hook_node_view and #attached

/**
 * Implements hook_node_view().
 */
function MYMODULE_node_view($node, $view_mode, $langcode) {

  // Add content type specific JS on full page node view
  if($view_mode == 'full'){
    switch($node-&gt;type){
      case 'article':
        $node-&gt;content['#attached']['js'][] = array('data' =&gt; drupal_get_path('theme', 'MYTHEME') .'/js/article.js');
      break;
      case 'page':
        $node-&gt;content['#attached']['js'][] = array('data' =&gt; drupal_get_path('theme', 'MYTHEME') .'/js/page.js');    
      break;
    }
  }

}