Polymer/core-ajax — pull request #41 by jmorille (2014-11-04 12:48:25+00:00)
Title: issues#37 : Add bodyType attribute to manage  JSON object in attribute body

Like it was discuted in the https://github.com/Polymer/core-ajax/issues/37#issuecomment-60758016

One possibility is to add the bodyType="json" to handle Json object in body to do like the jquery.post.