Trying to package posts for republishing by partner offsite

Have you considered using the RSS feed to import posts?

Another possible solution might be to use the export feature, the output is an xml file though not js. I found a program that will import the WordPress Exported file (which allows you to choose certain posts, all post, or posts between a certain date, or by category).

After you import the WordPress XML file you can generate; an HTML file, T.O.C, or a Word HTML file that consists of the exported file content. I’m not sure what your destination site uses to display content, but it should have a way to import the data.