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Welcome to Introduction to React.js, Part I!

React.js is a JavaScript library. It was developed by engineers at Facebook.

Here are just a few of the reasons why people choose to program with React:

  • React is fast. Apps made in React can handle complex updates and still feel quick and responsive.

  • React is modular. Instead of writing large, dense files of code, you can write many smaller, reusable files. React's modularity can be a beautiful solution to JavaScript's maintainability problems.

  • React is scalable. Large programs that display a lot of changing data are where React performs best.

  • React is flexible. You can use React for interesting projects that have nothing to do with making a web app. People are still figuring out React's potential. There's room to explore.

  • React is popular. While this reason has admittedly little to do with React's quality, the truth is that understanding React will make you more employable.

If you are new to React, then this course is for you! No prior React knowledge is expected. We will start at the very beginning and move slowly.

If you are new to JavaScript, then consider taking our JavaScript course and then returning to React.

The three Codecademy React courses are not a high-level overview. They are a deep dive. Take your time! By the end, you will be ready to program in React with a real understanding of what you're doing.

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