Redux: What, Why, How, When, and Where to Use It

Introduction

State management is one of the trickiest parts of building large applications, especially in React. If you've ever struggled with prop drilling or managing state across multiple components, you might have heard about Redux. But what exactly is it, and should you use it? Let’s break it down in simple terms.

What is Redux?

Redux is a state management library that helps store and manage application data in a single centralized place. It allows different parts of your app to access and update shared data efficiently without prop drilling or unnecessary re-renders.

Think of Redux as a global whiteboard where components can write and read data in a structured way.

Why Use Redux?

You might be wondering, “Can’t React’s built-in state do the job?” Sometimes, yes! But Redux is useful when:

✅ Your app has complex state (e.g., user authentication, shopping cart, etc.).
✅ You need to share state across multiple unrelated components.
✅ You want better predictability and debugging (Redux has great tools like Redux DevTools).
✅ You need better performance by avoiding unnecessary re-renders.

If your app is small and state is only needed in a few places, React’s useState and Context API might be enough.

How Does Redux Work?

Redux follows a simple three-part architecture:

Store → A single source of truth that holds the entire state of your app.
Actions → Plain JavaScript objects describing what should change in the state.
Reducers → Pure functions that take the current state and an action, then return a new state.

Example: Counter App in Redux

Here’s how a basic counter works using Redux:

1️⃣ Define an action:

jsCopyEditconst increment = { type: "INCREMENT" };
const decrement = { type: "DECREMENT" };

2️⃣ Create a reducer:

jsCopyEditconst counterReducer = (state = 0, action) => {
  switch (action.type) {
    case "INCREMENT":
      return state + 1;
    case "DECREMENT":
      return state - 1;
    default:
      return state;
  }
};

3️⃣ Create a store and dispatch actions:

jsCopyEditimport { createStore } from "redux";

const store = createStore(counterReducer);

store.dispatch(increment);
console.log(store.getState()); // Output: 1

When Should You Use Redux?

Use Redux when:
🔹 Your app has a lot of shared state across multiple components.
🔹 You need predictable state updates and debugging tools.
🔹 Performance optimization is required by avoiding unnecessary renders.
🔹 The app is scalable and will grow in complexity over time.

Avoid Redux if:
❌ Your app has simple state that can be managed with useState or useContext.
❌ You’re working on a small project where Redux would add unnecessary boilerplate.

Where is Redux Used?

Redux is widely used in React applications, but it’s not limited to React. It can also be used in:

Angular and Vue apps (though less common).
Large-scale web applications (like e-commerce, dashboards, and enterprise apps).
Mobile apps with React Native (for managing global state).
Server-side applications (sometimes for managing API responses efficiently).

Well-known companies like Meta (Facebook, Instagram), Airbnb, and Twitter use Redux for handling their complex state needs.

Final Thoughts

Redux is powerful but not always necessary. If you’re building a small project, React’s built-in state management is often enough. But for larger applications with complex state needs, Redux can be a game-changer. The key is to evaluate your project’s needs and choose the best tool accordingly!