Did you see this one: https://appstore.mendix.com/link/app/Document%20Viewer
If you want to preview files in the browser you could try building a solution that works with Office web viewer. You'll need to construct a url for the document that looks like:
In addition you'll need to make the document available via a url. For more information see: this site
Another option would be to use some jquery to display the documents via the Google documents viewer, see this stack overflow site for more info.
Hope this helps you further in creating functionality to preview word documents in the browser.