Table of contents
1.
Introduction
2.
What is render() in React.js?
3.
Why do we need the render() in react js?
3.1.
Syntax of render() in react js
4.
Rendering Elements
5.
Frequently Asked Questions
5.1.
How do rendering and mounting differ in React?
5.2.
How do props work in React?
5.3.
When should you use render in React?
5.4.
In React, what is the DOM?
6.
Conclusion
Last Updated: Mar 27, 2024

Use of render() in React js

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Introduction

React applications interpret the code in our components as elements mounted on the page's DOM. Front-end developers have to deal with rendering regularly. A browser can understand and display react components by rendering them DOM (Document Object Model) nodes.

Manipulation of the DOM takes an exceptionally long time. React elements, on the other hand, react much more quickly. To take advantage of this, react creates a virtual representation of what the DOM should look like, called the Virtual DOM. Let's look into render() in react js in more detail.

Also See, Dropdown in React JS

What is render() in React.js?

There is only one required method in a class component in React, the render() in react js method, which describes the view rendered to the browser. React's virtual DOM concept tricky because of how cleverly it works, and there are certain subtleties to the way it works. React calls render() when it creates or updates a component in various stages of an app. It returns a JSX without taking any arguments. It contains the view hierarchy of the component it is assigned to. The view hierarchy will later be converted to HTML for display in the browser.

The render() in react js is the most important part of the react lifecycle because the class components cannot be rendered without it.

Components can be created in two ways in react.js.

  1. Class components
  2. Function components

 

It is necessary to use the render method if the class contains a component.

React invokes the render() method for class components. Originally, class components were introduced so you could define lifecycle methods and maintain state by creating an object.

Using a functional component, you create a function that returns your object. A functional component replaces a class component's render method. Functions, however, cannot maintain a state and cannot provide additional functions for lifecycle methods to hook into.

Why do we need the render() in react js?

React runs its applications by batching together all of the changes you make, such as entering text, removing an element, adding an element, etc. It then compares this virtual representation with the real DOM, finds what needs to be updated, and makes possible minor changes to the actual DOM to keep the two in sync while maintaining performance.

React describes this in two phases:

i) Render phase: In this phase, react starts at the root and descends to the leaf component, invoking the create element method to transform the JSX-based components into react elements that are rendered and stored. Javascript objects that describe the user interface are called react elements. To convert the JSX into React elements, the entire component tree must be converted, which is then passed to the commit phase.

ii) Commit phase: The react DOM package applies to react elements to the DOM.

The UI is updated with the render() in react js. A new element must be created and sent to ReactDOM.render(). An element in React cannot be changed once it has been created, and its attributes cannot be changed after the element has been created. Therefore, a single element can be compared to a single frame that depicts the UI to some extent. The content of the container node is controlled by ReactDOM.render(). If any DOM elements are present in the container node at the first call, they are replaced.

Syntax of render() in react js

ReactDOM.render(<p>Render method</p>, document.getElementById('val'));
You can also try this code with Online Javascript Compiler
Run Code

 

<body>
  <div id="val"></div>
</body>


Output:

Rendering Elements

As the building blocks of the react app, the elements specify what will appear in the user interface. These elements are DOM nodes that define the content we wish to appear on the screen.

We will create our first react element using JSX. First, open the index.jsp file from the src directory. This is the simplest method to create a react element.

const val = ReactDOM.createRoot(document.getElementById('val'));
const element = <h1>React Elements</h1>;
val.render(element);
You can also try this code with Online Javascript Compiler
Run Code

 

This object is called an element, and we have a sign into a variable for H1. This object must be rendered into the browser Dom, and for that, we will use a container. Index.htm, we have a Div named root, and we will use that div as the container.

By writing the following code, the above created element can be rendered into it:

<div id="val">
</div>


Output:

Check out Advantages of React JS here.

Frequently Asked Questions

How do rendering and mounting differ in React?

A class-based component called render gets called and returns instructions to create the DOM. UI components mount when they render for the first time, constructing the initial DOM structure.

How do props work in React?

React components accept props as arguments. Those arguments are passed to components through HTML attributes. Properties are the arguments passed to components.

When should you use render in React?

A front-end developer must manage rendering as an essential process. A React component must have the render() method to describe how the view will be rendered to a browser window.

In React, what is the DOM?

DOM is an acronym for Document Object Model. A structured representation of the HTML elements that make up a webpage or web application is known as a schema. Schema is a structured representation of the HTML elements that make up a website or web application. The DOM represents the entire user interface.

Conclusion

This blog shows what render() in react js is and why we need the render(). We have also seen how to render elements. Here are some blogs like React Render and Render OptionsRendering Elements in React Js which you can refer to learn more about render() in react js.

Recommended Readings:

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