This blog will cover a comprehensive guide to React re-rendering, its components, and its types. You will get an overview of React components with an example.

1. Kuldeep Tarapara
April 17, 2023
Everything to Know About React Re-
Rendering: A Comprehensive Guide
Table of Contents
1. What Is A Necessary And Unnecessary Re-Render?
2. When Does the React Component Re-Render?
3. Steps of React Re-rendering Component
4. Reasons for React force Re-Render: Parent Re-Renders
5. Conclusion
6. Frequently Asked Questions (FAQs)
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2. React JS is an open-source JavaScript library that can be used for easily creating the
user interface. These are speci몭cally designed for single-page applications. These are
also known for providing a quick user experience by updating certain features in the
UI.
Rendering components involves the React Component Lifecycle, so these are also
called various app stages due to the result of the user interacting with the app or
external data. It could be processed based on an asynchronous request or
subscription model. Non-interactive apps do not enable asynchronous data updates,
which do not re-render.
React force rerender can be extensively caused by the three reasons listed as follows:
Update in prop
Re-rendering of the parent component
Update in State
What Is A Necessary And Unnecessary Re-
Render?
1. Necessary Re-Renders
In React, the render() method is involved with class components. These are also
responsible for extensively describing views on rendering with browser windows.
These can be enabled in a clever way, as React operates on the virtual DOM concept.
For example, if the user types a word in the input, this message will be updated on
every key press in the input 몭eld, i.e., re-rendered.
2. Unnecessary Re-Renders
The app cultivates the re-rendering of a component via the various re-render
mechanisms, which are either a mistake or inappropriate for the app’s architecture.
Unnecessary re-rendered by themselves are simple, as it makes React fast and able to
deal with them without noticing anything about the users.
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3. Re-rendering React components will slow down the app unnecessarily. These could be
making the UI feel entirely unresponsive. Normally, this process could affect the
performance level of the app, which will cause a loss or even side effects.
When Does the React Component Re-Render?
1. Context Changes:
The value of Provider can change with the components, so it is used with Context on
re-rendering. These can be easily accessed even with the data directly.
Re-renders are also not prevented directly by memorization. It also involves fewer
workarounds, which could be stimulating. So it also prevents re-renders, which are
enabled by the context.
2. Parent Re-Renders:
The component is re-rendering itself only when the parent re-renders in the system.
These can be easily enabled in opposite directions. The component could be re-
rendered with the children.
The process can also be enabled with the tree so the re-rendering in the child does not
trigger with the re-rendering of the parent. It also involves the edge case and caveats,
enabling the mystery of the React element with the parent and children and re-renders.
3. Hooks Changes:
Hooks changes are one of the common reasons for Re-renders, so these can be
extensively happening with the hook, such as “belongs.” It can be extensively added to
the components with an added feature. The same rules are involved with context
changes as well as state changes.
Typically, the state changes with the hook enabled with the trigger are wholly
unpreventable and re-rendered with a “host” component. These also involve triggering
the unpreventable re-rendering in the “host” component. It can be enabled by using

4. context and having the context’s value change on a different level.
Hooks are also chained to different levels. A single hook in the chain still involves
“host” components. Below is the reason for creating the simple Counter React Project
to understand the concept of re-rendering components.
4. State Changes:
When the React component’s state changes, it will re-render itself. Usually, it operates
either in the callback or in the useEffect hook. Also, State changes are the “root”
source of all re-renders.
5. Props Changes :
For props to be modi몭ed, they must be updated by a parent component, which means
that a parent component must be re-rendered to have the trigger re-rendered of a child
component regardless of its props; however, when the memoization techniques are
used with React.memo or useMemo, then the props upgrade becomes necessary.
Steps of React Re-rendering Component
Step 1: Create React project called a counter-app by
running the below command
Step 2: Open the project folder
Step 3: Install the required module by running the below
command to create React JS application
Step 4: Open VS Code
Go to the explorer in VS Code
Go to the src folder
1. npx create­react­app counter­app
1. cd counter­app
1. npm install react­desktop

5. New 몭le
Name it Child.js
Step 5: Edit code in the App.js
The app.js 몭le has the following code.
The state declared change and caused the re-rendering of App.js.
Step 6: Make a Child component
Step 7: Child.js will have the components
These give messages each time components render a function. Every time the count
button is clicked, the state change is triggered.
All the state changes in the parent component trigger re-rendering for subsequent
child components.
Reasons for React force Re-Render: Parent Re-
Renders
1. import { useState } from 'react';
2. import './Style.css'; // CSS file for style
3. import Child from './Child'; // Child Component
4. function App() {
5. const [Count,setCount]=useState(0);
6. console.log("Parent rendered");
7. return (
8. <div className="wrap">
9. <button onClick={()=>setCount(Count+1)}>
10. Increase
11. </button>
12. <p>Count:{Count}</p>
13. <Child name={"ABCD"}/>
14. </div>
15. );
16. }
17. export default App;
1. New File and name Child, js

6. Usually, the React component can easily re-render itself under various circumstances.
React schedules with the rendering of the time state with changes. These also involve
scheduling renders, which is quite time-saving to some extent.
These are extensively done by updating the reach and triggering it using the useState
function. This allows us to easily enable the state variable in the functional
components in ReactJS.
Re-renders could occur solely on the newer page that is requested. It ensures the
result is server-generated with the new HTML document. These can be extensively
sent to the browser to achieve excellence.
Re-rendering is quite similar to that of a snapshot taken with a camera. The camera is
helpful for checking the difference between an older snapshot and newer snapshots
generated with the state change. The following components will be re-rendered:
1. The Receiver Component:
It involves re-rendered as the consuming Context that receives updated context value
from the provider
2. Receiver Component’s Children:
State change with parent component resulting in re-rendering of its children
Conclusion
Context provider component updates with the React state management. These will be
enabled with the updates to the context value. This also causes all components
consuming the context to re-render.
Therefore, knowing when and why React re-renders components is vital for optimizing
the performance of your application. By using the React in-built tools and integrating
modernization techniques, you can signi몭cantly reduce the number of necessary re-
renders and improve the overall performance of your React application.

7. If you want more information about the React Re-render component, consult with
experienced React app developers who will give you complete knowledge about React
components in detail, which will help you make the application better with an
appropriate budget. So, let’s get started.
Frequently Asked Questions (FAQs)
1. What is re-rendering in ReactJS?
Re-rendering occurs when React updates its app with new information. Usually, this
exists due to user interaction with an app, a few external data points coming through
an asynchronous request, or some other subscription model.
2. How do you prevent re-renders on React functional
components?
Re-rendering can be done simply by exporting components using React.memo. React.
memo tells React to compare component props with its older props and only re-render
if they are different.
3. How do I check component re-rendering in React?
A checkbox hidden in ReactDevTools settings allows you to highlight the components
that were re-rendered visually. Hence, to enable it, go to “Pro몭ler” >> click the “Cog
Wheel” on the right side of the bar >> “General” tab >> Check the “Highlight updates
when components render” checkbox.
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