React - The Essential Concepts

Mobile & Web

Anna Sedlar

React is an increasingly popular javascript library created by Facebook and used by major companies including Lyft, Paypal, Netflix, Reddit, The New York Times, and Walmart. Used only for rendering HTML, React is not a full framework and thus is only the “View” section of the Model-View-Controller web development framework. React conceptualizes a view as many small, modular pieces and excels in creating interactive, stateful, and reusable components. Other essential React concepts include: a virtual DOM that selectively renders state changes and updates only the necessary components, so that an entire page refresh is not required; JSX, React’s version of a templating language that allows combined HTML and Javascript to create immutable “React elements” which are then injected into the DOM; props (properties), which are attributes added to components by passing them down from parent components in order to render data dynamically; and various component lifecycle methods that allow code to run at particular times, either right before or after an event occurs.