factory.js

angular.module('umbraco').factory('MyPropEditorClipboardActionHandler', function clipboardFactory() {
  return {
    handle: function () {
     // Do something 
    }
  }
});

package.manifest

{
    // I'm a prop editor developer so I'll define my actions inline
    "propertyEditors": [
        {
            "alias": "MyPropEditor",
            "name": "MyPropEditor",
            "editor": {
                "view": "~/app_plugins/MyPropEditor/views/propertyeditors/MyPropEditor.html",
                "hideLabel": false,
                "valueType": "STRING"
            },
            "actions": [
                {
                    "labelKey": "clipboard_labelForRemoveAllEntries",
                    "labelTokens": [],
                    "icon": 'trash',
                    "handler": "MyPropEditorClipboardActionHandler"
                }
            ]
        }
    ],
    // I'm a developer who wants to extend an existing prop editor so I'll define my actions here
    "propertyActions": [
         {
             "propertyEditor": "MyPropEditor",
             "labelKey": "clipboard_labelForRemoveAllEntries",
             "labelTokens": [],
             "icon": 'trash',
             "handler": "MyPropEditorClipboardActionHandler"
         }
    ]
}