What is React JS? It's a JavaScript library for creating user interfaces, to put it simply. Let's start with the fundamentals before moving on to the rest of the React JS course. There are two words in this definition: javascript library and user interface. Let's have a look at what these terms signify. The library is a collection of pre-written code that is efficient, complicated, well-written, and easily accessible. As a result, it simplifies our lives and allows us to use code written by others with ease. Assume we wish to find the cosine value of 20. Rather of obsessing over how this library was created, we simply use the math library. For instance, Math.cos (20). The user interface is what the user sees right away. React JS is a powerful tool that breaks down a page into many building elements known as components, allowing for fast front-end development. React JS pre-requisites There are some prerequisites to bear in mind before we plunge into the depths of our React