A React app should not contain application logic in the presentation components. These components are used to implement interactions with users, send user input, and so on. Child components should never call the parent API directly. However, they may give the child a function reference and invoke it without knowing the parent’s name. React also supports the use of components as delegates. In a React app, delegates are essential for the smooth interaction between user interface components and the backend.

React allows developers to develop responsive, lightweight, and scalable web applications. In a typical web app, the DOM contains a collection of HTML elements. When a user presses a Comment button, the entire DOM would update. Instead, React allows the user to selectively update a portion of the DOM without reloading the entire page. The responsiveness of this approach is one of its main benefits.

React requires complex build tooling, which reduces the code maintainability. It involves four steps called transpilation. This process makes it difficult to debug, and can take years to learn and master. Because React files are unreadable by web browsers, developers don’t need to understand the latest HTML markup specification. In addition, developers don’t have access to many of the latest browser features. These are just a few of the disadvantages of React.

Before React JS, web applications were written in vanilla JavaScript. The use of jQuery was less UI-focused and required a longer development time. Moreover, developers had more chances to make mistakes when using these outdated tools. To solve these problems, Facebook software engineer Jordan Walke created React JS in 2011.