~$ man react
What is React?
definition
React is an open-source JavaScript library created by Facebook for building user interfaces in web applications. It focuses on the view layer and enables developers to create reusable UI components.
It uses a virtual DOM to track changes and update only the necessary parts of the page, improving performance. React also supports JSX, a syntax extension that mixes HTML-like code with JavaScript.
Think of React like building a house with Lego bricks where each brick is a self-contained component such as a window or door that you can reuse or swap without rebuilding the whole structure.
key takeaways
- React breaks interfaces into independent reusable components.
- It relies on a virtual DOM to minimize direct browser updates.
- JSX lets developers write markup inside JavaScript files.
- State management handles data changes across components.
- A large ecosystem includes tools like React Router and state libraries.
the 2026 job market
In 2026 React skills remain a baseline requirement for frontend and full-stack roles across SaaS and web product teams, with demand steady in companies maintaining large codebases and migrating legacy apps.
frequently asked questions
Is React a framework or a library?
React is a library focused on the UI layer. It does not include routing or state tools by default, unlike full frameworks such as Angular.
How does the virtual DOM work in React?
React keeps a lightweight copy of the real DOM in memory. When data changes it compares the copies and updates only the differing parts in the browser.
What is JSX and why is it used?
JSX is a syntax that lets developers write HTML-like tags inside JavaScript. It compiles to regular JavaScript function calls and improves readability.
Can React be used for mobile apps?
Yes. React Native uses the same component model to build native mobile interfaces for iOS and Android from a single codebase.
