getText() not always returns string

[Tobiasz Cudnik]

For empty nodes, getText() will return undefined instead of empty string. According to jsdoc, this method returns string.

Sample testcase

1. Using "Replace Textarea by code" example, fill editor with content:

   <h1></h1>
   

2. Evaluate this code:

   var e = CKEDITOR.instances.editor1;
   var text = e.document.getBody().getChild( 0 ).getText();
   console.log(typeof text);
   CKEDITOR.tools.trim(text);
   

3. Results in "TypeError: str is undefined" from CKEDITOR.tools.trim

Please correct me if my point of view is incorrect.