What and Why React js

 What is React js…?

React js is a JavaScript library that is open source for building user interfaces.

The two key points above definition are React js is a JavaScript library. It is not a framework.

The second key point is the building of user interfaces.

So, React js does not give importance to other factors such as routing or HTTP requests. Its sole purpose is to create rich user interfaces.

Now, You don't have to be concerned about how you'll manage routing, HTTP, and other features now.

React js has a large ecosystem, works well with other libraries, and can be used to create full-fledged web apps.

Reasons you might want to learn React js…

We now understood what React js is and how it is used. Let's look at some of the reasons you might want to learn React js.

Let's start with the fact that React js is a Facebook project that is developed and maintained.

You can be sure that when a company like Facebook uses React js in its own products and invests money and resources to keep the project alive, it isn't going away anytime soon.

By learning React js, You have a great chance of landing a front-end developer job you've always wanted.

Technical aspects of React js and why it is a good choice…

Now let me touch slightly on the technical aspects of React js and why it is a good choice.

React js has a component-based architecture and this let you break down your application into small encapsulated parts which can then be composed to make a more complex UI.

For example, a traditional website can be broken down into header, sidebar, nav, main content, and footer.

Each section represents a component that, when composed in the right way, make up the entire website.

Components also make it possible to write reusable code. For example, you could have a component for an article on React js.

The same component can be reused for articles on Angular or Vue by simply passing the right data into the article component.

For enterprise applications, the ability to reuse code is a huge plus point.

Another key point is that React js is declarative. Now, what does that mean?

Basically, we just have to tell React js what we want. DOM Library will build the actual UI. This is the declarative paradigm and this is in contrast with the imperative paradigm we are usually used to which implements algorithms in explicit steps.

Let me give you a relatable example.

Let's say you go to an artist. You ask them to draw a landscape. You don't tell them how to draw it, it's up to them.

This is declarative. You tell what has to be done and the artist will get it done for you.

And the same task you ask of a 5-year-old child. But, this time you tell them to first draw the mountains, then the river, then the trees, and so on.

You explicitly specify each step and you control the flow of the landscape which is an imperative paradigm.

Why this is important to understand is because React js is declarative. You have to tell react what the UI should look like and react will create the actual UI. React js will make it painless for you to create complex UI's by abstracting away the difficult parts.

React js will handle efficiently updating and rendering just the right components in your application when your data changes, DOM updates, which is one of the more expensive operations, are handled gracefully in React js.

Now React js also makes no assumptions about the rest of the technology stack you're using for your project. You can seamlessly integrate react into any of your applications.

Be it just a part of the page or a complete page, or even an entire application itself, React js will fit right in.

And once you have a good knowledge of React js, you can also enter the world of mobile applications with React native. The bottom line is that React js will be a great addition to your skillset.

What are the prerequisites to get started with React…?

Let’s see what are the prerequisites to get started with React?

HTML, CSS, and JavaScript fundamentals are absolutely necessary for this course. I will also be making use of ES6. So, a knowledge of modern JavaScript is also essential.

You don't have to be an expert by any means, but there are a few features that make it so much easier to write react code and that is why I recommend learning to React js with ES6.

With JavaScript, make sure you are aware of this keyword, map, and reduce methods. Mainly the map method.

With ES6, please go through ‘let’ and ‘const’ declarations, arrow functions, template literals, default parameters, object literals, and rest and spread operators.

No prior knowledge of any other JavaScript libraries or frameworks is necessary.