Why React?

Introduction

With so many ways to build a website — plain JavaScript, jQuery, Angular, Vue, and more — it is fair to ask why React specifically has become so popular. The answer is not that React is the only option, but that it solves a very common, very painful problem in a way that scales well as applications grow.

This lesson looks at exactly what that problem is, why so many developers and companies have chosen React as their answer to it, and how React compares at a high level to plain JavaScript DOM manipulation and other popular frameworks.

The Problem React Solves

Imagine building a shopping cart with plain JavaScript. Every time an item is added, you need to find the right DOM elements, update the item count, recalculate the total, and make sure the "empty cart" message disappears if it was showing. As more features get added — discounts, quantity changes, out-of-stock items — the code that keeps the DOM in sync with your data grows tangled, and it becomes easy to forget to update some part of the screen.

This is the core problem: manually tracking every possible DOM update, for every possible data change, does not scale. Small oversights lead to UI bugs — a total that does not update, a badge that shows stale data — and those bugs get harder to trace as an application grows.

Why Developers Choose React

Beyond solving the DOM-synchronization problem, several practical factors have driven React's widespread adoption.

React vs Plain JavaScript

Plain JavaScript (sometimes with jQuery) is perfectly capable of building interactive pages, and it is worth understanding since React is built on top of it. The difference shows up as an application grows: with plain JavaScript, you are responsible for manually finding elements and updating them every time data changes. With React, you describe the UI as a function of your data, and React handles finding and updating the right DOM nodes.

React vs Other Frameworks

React is not the only tool built to solve this problem. Angular and Vue are two other widely used options, and it helps to know roughly how they differ — this is just an orientation, not an exhaustive comparison.

Example: The Same UI, Two Ways

Here is a simple "like" button, first with plain JavaScript and then with React, to make the earlier comparison concrete.

const likeBtn = document.getElementById("like-btn");
let liked = false;

likeBtn.addEventListener("click", () => {
  liked = !liked;
  likeBtn.textContent = liked ? "❤️ Liked" : "🤍 Like";
});

function LikeButton() {
  const [liked, setLiked] = useState(false);

  return (
    <button onClick={() => setLiked(!liked)}>
      {liked ? "❤️ Liked" : "🤍 Like"}
    </button>
  );
}

❤️ Liked

Common Mistakes

Best Practices

Frequently Asked Questions

Key Takeaways

Summary

React exists to solve a real, common problem: keeping complex, frequently-changing user interfaces in sync with underlying data without writing brittle, manual DOM-update code. Its popularity comes from a combination of that core benefit, a huge ecosystem, strong reusability, and extensions into mobile and full-stack development.

In this lesson, you learned the problem React solves, why developers and companies choose it, and how it compares to plain JavaScript and other frameworks like Angular and Vue. Next, you will look at how React is architected internally, including the component tree and one-way data flow.