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Lesson 07 · ReactJS Tutorial

State with useState

State allows a component to remember information that can change over time. This is what makes React interfaces interactive rather than static.

Core Explanation

State allows a component to remember information that can change over time. This is what makes React interfaces interactive rather than static.

The key habit is to treat state as the source of truth. If the user interface depends on changing data, that data should usually live in state.

Key idea: A learner should be able to explain State with useState in plain language before moving on to the next lesson.

Worked Examples

Use the examples below to connect the theory with syntax. The first example shows the basic pattern. The second moves closer to how the idea often appears in real applications.

Example A

const [count, setCount] = useState(0);

Example B

<button onClick={() => setCount(count + 1)}>Count: {count}</button>

Try changing variable names, labels, values, or returned JSX in each example. Even a small change helps you understand the pattern more deeply.

Mini Simulation

Counter Demo

Increase and reset a state value.

How It Fits Into a Real App

React concepts become more useful when you connect them to actual application design. For example, a dashboard might combine reusable components, state, events, conditional rendering, and API fetching all on one screen. A learning portal may add routing, validation, shared state, and persistence on top of that.

This lesson should therefore be thought of as part of a larger React workflow. The goal is not just to memorize syntax, but to understand when this concept helps make the interface clearer, more interactive, or more maintainable.

Main topic
State with useState
Typical use
Often used inside practical React projects rather than in isolation.
Learning goal
Understand both the syntax pattern and the reason a developer would choose it.

Lesson Summary

By the end of this lesson, you should be able to recognize the role of State with useState, read common examples confidently, and adapt the pattern into a small practice component of your own.

Exercises

  1. Practice task 1 for State with useState.
  2. Practice task 2 for State with useState.
  3. Practice task 3 for State with useState.
  4. Practice task 4 for State with useState.
  5. Practice task 5 for State with useState.

Practice before moving on

Rebuild one of the examples from memory, then modify it slightly. That is one of the fastest ways to turn recognition into working skill.

Continue to the next lesson →