All the fundamental React.js concepts, jammed into this single Medium article

This article is not going to cover what React is or why you should learn it. Instead, this is a practical introduction to the fundamentals of React.js for those who are already familiar with JavaScript and know the basics of the DOM API.

All code examples below are labeled for reference. They are purely intended to provide examples of concepts. Most of them can be written in a much better way.

https://medium.freecodecamp.org/all-the-fundamental-react-js-concepts-jammed-into-this-single-medium-article-c83f9b53eac2

Polymer vs. React: Comparing Two Front-end JavaScript Libraries

Polymer vs. React—which should you use? It’s a question that inevitably crops up whenever anyone discusses the components-based future of the web. While both Polymer and React are libraries created to support a component-oriented approach to front-end web development, they do so in very different ways. In this article, we’ll try to illustrate the role each of these technologies plays in front-end web development so that you can decide which is best suited for your needs.

https://www.upwork.com/hiring/development/polymer-vs-react/