You've already learned how to display data with React. Now let's look at how to make our UIs interactive

One of the first questions people ask when considering React for a project is whether their application will be as fast and responsive as an equivalent non-React version. The

ReactTestUtils makes it easy to test React components in the testing framework of your choice (we use

React is usually quite fast out of the box. However, in situations where you need to squeeze every ounce of performance out of your app, it provides a shouldComponentUpdate

It's a common pattern in React to wrap a component in an abstraction. The outer component exposes a simple property to do something that might have more complex implementation

shallowCompare is a helper function to achieve the same functionality as PureRenderMixin while using ES6 classes with React. If

The React add-ons are a collection of useful utility modules for building React apps. These should be considered experimental and tend to change more often

Note: cloneWithProps is deprecated. Use React.cloneElement instead. In rare situations, you may want

We'll be building a simple but realistic comments box that you can drop into a blog, a basic version of the realtime comments offered by Disqus, LiveFyre or Facebook comments

In most cases, you can use the key prop to specify keys on the elements you're returning from render. However, this breaks down in one situation: