What is React?
React is a JavaScript library for building user interfaces out of small, reusable pieces called components. A component is a function that returns what should appear on screen. When your data changes, React updates the page for you.
In these lessons the example code runs live in your browser. Define a component named App and it is shown in the result panel. The React hooks (useState, useEffect and friends) are already available, so you do not need import lines.
The HTML-looking part is JSX. It is JavaScript in disguise, and the next lessons explain it. Change the text and Run again.
What is a React component?
Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.
Tip: use the left and right arrow keys to move between lessons.