What does the use Effect hook do?

   Quality Thought – Best React JS Training Institute in Hyderabad with Live Internship Program

Looking to master React JS and kickstart a successful career in front-end development? Look no further than Quality Thought, the premier React JS training institute in Hyderabad. With a proven track record of training thousands of tech professionals, Quality Thought stands out for its industry-oriented curriculum, expert trainers, and a unique live internship program that bridges the gap between learning and real-world application.

React JS is one of the most in-demand front-end libraries today, powering user interfaces at companies like Facebook, Instagram, Netflix, and Airbnb. At Quality Thought, students are not only taught the fundamentals of React—including components, JSX, state management, routing, hooks, and integration with REST APIs—but also gain exposure to advanced topics such as Redux, React Context, and performance optimization techniques.

What truly sets Quality Thought apart is its live internship program, a rare offering among training institutes in Hyderabad. This program allows students to work on real-time projects under industry mentorship, simulating the experience of working in a software company. From task management using tools like Git and JIRA, to team collaboration in agile environments, students gain the practical skills employers are looking for.

A React component is a fundamental building block of a React application. It’s essentially a reusable, self-contained piece of code that defines how a part of the user interface (UI) should look and behave.

The use Effect hook in React allows you to perform side effects in function components. Side effects are operations that affect something outside the scope of the function being executed, such as data fetching, subscriptions, or manually changing the DOM. In class components, these side effects are typically managed using lifecycle methods like component Did Mount, component Did Update, and component Will Unmount. The use Effect hook combines these lifecycle methods into a single API for function components. 

Medium

+1

Geeks for Geeks

+1

legacy.reactjs.org

Geeks for Geeks

🧠 How use Effect Works

The use Effect hook accepts two arguments:

Effect Function: A function that contains the side-effect logic. This function is executed after the component renders.

Dmitri Palatine Blog

Dependency Array (Optional): An array of dependencies that determine when the effect should re-run. If any value in this array changes between renders, the effect function is re-executed.

React

Here's the basic syntax:

YouTube

java script

Copy

Edit

use Effect(() => {

  // Side-effect logic here

}, [dependencies]);

🔁 When Does use Effect Run?

After Every Render: If no dependency array is provided, the effect runs after every render.

Stack Overflow

+1

React

+1

Once on Mount: If an empty array [] is provided, the effect runs only once after the initial render, mimicking component Did Mount.

On Dependency Change: If specific dependencies are provided, the effect runs after the initial render and whenever any of the dependencies change, similar to component Did Update.

 Cleaning Up Effects

Some side effects require cleanup to prevent memory leaks, such as unsubscribing from a data stream or clearing a timer. To handle cleanup, return a function from within the effect function. This cleanup function is executed before the component unmounts or before the effect runs again due to a change in dependencies.

Read More

What is a React component?

What is the Virtual DOM?

Visit QUALITY THOUGHT Training Institute in Hyderabad