pdf-viewer
Publicly released: 2014
This project gives you a new HTML tag <pdf-viewer> that can be configured with the attributes src and width. Easy as that.
More specifically, this is a Web Component based on HTML5 Custom Element containing a React component providing a PDF viewer based on PDFjs. Since Custom Elements are not yet supported in all browsers, this project uses Webreflections document-register-element library.
If that weren't enough trendy buzzwords, the whole thing is written in ClojureScript employing Figwheel for an awesome development experience. Also it's not actually written in React, but in OM, a ClojureScript interface to React.