Rendering in React

All React components have logic and JSX. The render() function has a return statement which returns component template written in JSX. The code looks a lot like HTML, but it is actually JavaScript. JSX template defines what the component needs to look like and its custom functionality. So it’s very important.

The render() method is responsible for updating the screen when needed. Most of the time, dynamic appearance of elements depends on state and/or prop values. Whenever state and prop values change, React calls the render() method. This is the basic use for this important method. In this article, we’ll take a closer look at the render() method, when it is called, and other use cases.

Virtual DOM

This is one of the most important concepts in React. Virtual DOM is React’s internal image of what the page should look like. Whenever state and prop values change, React updates the mirror image (virtual DOM). Then React internally synchronizes this image with actual DOM and shows updates on the page. All of this happens very seamlessly and keeps React efficient. This allows us to implement great UX features like clearing form after it is submitted. More about that in this guide.

The render() method updates virtual DOM image of the component. The default behavior is that React updates virtual DOM for the component itself, as well as its children components. This would be inefficient for real DOM. However, virtual DOM is just a shadow image and much more lightweight. For this reason, React is fairly efficient and changes the DOM almost immediately.

An important distinction is that the render() function affects only virtual DOM. It does not render the actual HTML page. React automatically handles differences between virtual DOM and real DOM.

What does rendering mean?

Rendering refers to the action of displaying web apps on the screen. It is also commonly referred to as updating the screen. There’s even a componentDidUpdate() lifecycle method in React. You can use it to run a side-effect every time the component re-renders. In functional components, you use the useEffect() to do the same.

componentDidMount() lifecycle method refers to the time when the component is first rendered. Once it is rendered, then componentDidUpdate() taps into updates.

Class components vs function components

The render() method is an essential part of both types of components in React. Class components have a separate render() method. In addition to normal class properties, the render() method is explicitly defined. It is usually positioned at the end of class components.

In class components, render() does not accept any parameters. Its only purpose is to return a JSX code that represents component’s appearance and functionality.

Functional components are a little different. They only have a return statement. However, changes to state or props still triggers the render method. In a way, functional components are render() methods themselves. They are run whenever state or props changes, and update virtual DOM.

Functional components do accept one argument – the props object, which is used to pass down data from parent components to their children.

There’s practically no difference between render() in class components and functional components. Both work the same way and follow the principles outlined above.

Choosing a career in Tech

Starting a career in tech is a wise decision, but it is associated with many challenges. For once, it’s really difficult to decide on a specialty within tech. There are so many professions – from data scientist to front-end developer, and they are all different in their own ways. Also, as a beginner who’s interested in tech, it’s difficult to predict which path will be the most interesting.

Transitioning from one career to another is very common in the field of tech. In this article, we will discuss various different paths, their advantages and disadvantages. Let’s get started.

UI/UX Design

These professionals make sure that websites are easy and intuitive to use for website users. UI is short for user interfaces, in other words website structure and elements of it. UX is short for user experience. In other words, how users interact with a web application.

Someone working in the field of UI/UX design must have a good eye for design and making sure that websites are convenient. Person working in this position will be tasked with prototyping and creating mockups of the web application.

Knowing design tools like Adobe Photoshop and hard technical skills like HTML and CSS can go a long way. There are also wireframing and prototyping tools which you need to know.

Frontend development

This is a more technical field than UI/UX design. In this role, you will have to build website interfaces. In other words, define basic functions and appearance of a website.

This career path does not require you to have strong design skills. You need to have a strong proficiency in JavaScript. Also, strong knowledge in CSS and HTML is mandatory.

Backend development

This is the most technical specialization of those listed here. It involves creating algorithms and other basic code which will be the ‘brains’ of web and native applications. In this role, you might have to create an API or even maintain databases. API will process requests from other devices, do calculations and provide an answer.

Go for this role if you like maths, writing algorithms, and processing data.


These days companies collect large volumes of data. Cybersecurity professionals are people tasked with protecting that data. Also you will need to ensure that applications continue running and are not turned off by cyber attacks.

A typical tasks for cybersecurity professional is to test, analyze and develop protection against possible attacks. Sometimes individuals in this role even have to play a role of a hacker to try breaking down defenses of a website or an online service. This is done to detect possible gaps in the defense and then working to fill those gaps.

Graphic design

This career is not very technical. It is only on this list because it involves the use of advanced software. Go for this role if you’re good with computers but also love art and drawing yourself. Graphic designers create beautiful visuals to highlight the brand and for marketing campaigns.