Why is React Js called as Single Page Application - reactjs

Hello guys i am new to React Js i often hear and see posts regarding react is single page app but never understood what is SPA and many say that it doesn't reload the pages but i didn't understood why so could you guys please explain me with simple examples.

A Single Page Application is a web application or website that interacts with the web browser by dynamically rewriting the current web page with new data from the web server, instead of the default method of the browser loading entire new pages.
This means that the URL of your website will not change completely (page will not reload), instead it will keep getting content and rewriting the DOM with it instead of loading a new page.
The goal is faster transitions that make the website feel more like a native app
Example: Netflix
This is the dashboard, and when we click on any movie, it changes to /watch and the content is rewritten.
In Technical Terms:
When building your react-app, you can see that there is only one
App.js from where your entire web-app is loaded in fragments and
components. This behaviour of rendering components and pages on a single page and changing the DOM( is a single page behaviour and hence the name), instead of loading a new page with new content, this makes it feel like a single application.

As mentioned in Glossary of React Terms:
A single-page application is an application that loads a single HTML page and all the necessary assets (such as JavaScript and CSS) required for the application to run. Any interactions with the page or subsequent pages do not require a round trip to the server which means the page is not reloaded.
And about "Why is React Js called as Single Page Application":
Though you may build a single-page application in React, it is not a requirement. React can also be used for enhancing small parts of existing websites with additional interactivity. Code written in React can coexist peacefully with markup rendered on the server by something like PHP, or with other client-side libraries. In fact, this is exactly how React is being used at Facebook.

A single page application has one single page e.g. www.google.ch. It is exactly one HTML file (with all its required dependencies) loaded into the browser. You'd navigate between paragraphs only using hash-router, but never ever visit another page like www.google.ch/maps (that would then be www.google.ch/#maps, which references / -> index.html) (tho google may not be the best example, it is more about URIs).

ReactJS is an open source JS library for building UI and used for SPA, and it manages the views of web apps. Reactjs can help you to modify your data without reloading of a page. It is a popular library in the market trend because of its scalability & fast performance.
Single Page applications are different from multiple page apps that we see everywhere because the SPA doesn't move into new pages; instead, it will load the pages inline within the same page.

In traditional websites, when we go from one page to another, the whole site is loaded. e.g - if you go from "www.example.com/hi" to "www.example.com/hello" the whole website is reloaded. No matter how much portion of the website is really changed. Let's say, the website has "Sidebar, logo, menu" on both of its pages, then the full reload doesn't make any sense. This takes too much time and decreases the performance.
Single Page Applications, as the name suggests, have only one single page that is loaded the first time you open the website. After this, no matter where you click, it is not gonna refresh the website fully.
browser reload button
The loading icon of the browser doesn't load when we move from one page to another on SPA site, as it does on the traditional websites.
Cons- SPA sites are great for UI UX but they are not the best when it comes to Search Engine Optimisation, it creates problems with rankings.

Related

How would I make a large website with React, if React makes SPAs

I want to use react js to make a news website with hundreds of articles. As I understand it, react makes single-page-applications. Surely it is not feasibly to include hundreds of articles in a single-page-application, so how could this be done?
You can absolutely use react to make a single page application which shows hundreds of articles.
The term single-page application describes how the articles are loaded when the user moves between the articles. In a multi-page application, every article will be its own html file. When the user clicks to go to a new article, your server sends a brand new html file, and the browser throws out the old page and shows a new one. In a single-page application, there's just one html file which is loaded at the start. As the user navigates between articles you use javascript to fetch data about that article (but not a full html file), and then you use that data to modify the existing page to look like a new page.

Is Next.js app an SPA or single page application?

Plain React apps are called SPA because they have only one html page which is the index.html. But that is not the case for next.js. So can we call a next.js app a single page application?
Good question.
Normally we don't call an engine SPA or not. For instance, React can do SPA, but it can do non-SPA work as well. The same applies to the NextJS as well.
Just to follow your dictionary. NextJS by default is not SPA based due to its hybrid nature, because it publishes each page as a separate entry point for everything under /pages. Of course if you only have one page index.js, then technically it's a SPA again. I guess it depends on how you structure your pages.
Yes, we can call nextjs a SPA even if you create many pages, but to keep it as such you should use client side transitions (no <a> tag).
First of all, SPA = Single Page Application
I assume the question intend SPA vs MPA (Multi Page Application)
The answer is Nextjs can do both depending if you use next link
https://nextjs.org/docs/api-reference/next/link
That will perform a client side transition without reloading the page from the server, assuming your page is static of coure and does not use getServerSideProps(). You can check that by watching the Network in Chrome debug tools.
How that works ? On first page load, all pages get loaded in js inside the vdom and any page can get injected into your browser dom fromthe client js not from the server.
To give it an MPA behavior, you can also link a relative page with a simple html anchor tag <a>, that will reload the page from the server, as the a tag uses no js for that. What could be the advantage of that ? keeping code clean from next maybe, and if you mess the react vdom (which you shouldn't) you're sure to get a fresh page again. A disadvantage of that is that you loaded all content in js initialy anyway, so reloading with anchors is a waste of resources and load time.
Note using PWA (Progressive Web App) is also an option to optimise the user experience, and it is also supported by nextjs
see
https://nextjs.org/docs/faq
and
https://github.com/vercel/next.js/tree/canary/examples/progressive-web-app

Split React Single page app into several Single Page Apps for faster loading?

This may sound weird at first but please read until the end. Generally Single Page Applications
(SPAs) consists of a single index.html and several JS scripts and routing is handled via Javascript with libraries like React Router, so the first load is slow because you are loading the entire application. So with the advent of Progressive Web Apps and Service Workers would not be better to split your Single Page Application into several SPAs for faster loading? Auth state and other shared state could be stored in Local Storage like for example Firebase does it. What are the issues with this approach?
As a comment from Sam already mentioned you should use code splitting to speed up the loading of your application.
You can start off by code splitting your app by the routes and build up from there.
Try using React.Suspense and React.lazy it should be a fairly quick process and you will see immediate results. Monitor the 'Network' tab in the dev tools and you will see different chunks loaded as you navigate your application.

Add an additional page to an Angular SPA

The Scenario
I'm developing the front-end (CSS only) of an Angular SPA.
I'm not especially familiar with Angular routing.
I'd like to add a standalone page containing Bootstrap components just for development purposes (yes, I know this means it won't be a single page application anymore). This way I have one unified view with all the components so I don't have to switch back and forth while working on the CSS. It also acts as documentation for the Bootstrap for the other devs to refer to.
What I've tried
I originally added a bootstrap.html page to the app folder, alongside the app's index.html This worked at first, but has now stopped working. What would be the best/standard way to achieve something like this?
Update: I've managed to fix some of the JS errors, so the page is up and running again. My question remains though: "is there a way of adding a standalone page that is considered standard/best practise, or is it literally just add a separate HTML page at the app root?"
If you use a target='_self' in your linking anchor tag, this should force a full page reload, and that will avoid the angular routing - which is where I expect your request is getting hijacked (by design).
e.g.
link
Answering your updated question
Not to my knowledge, since (as you correctly pointed out) this mixes the SPA design pattern.

Can I manually override google optimize redirect, and avoid external redirect?

I'm running A/B redirect tests with Google optimize, using SPA on React, Redux platform.
A problem I'm trying to solve is - redirecting to the new page causes the full page reload, which I would like to avoid and rather prefer to do it manually, so it would be seamless for a user and much faster.
Is there a way to do that?
Although this is a three years old question, maybe there are still users like me have the same issue.
Now Google has provided Activation events to resolve dynamic websites and single-page apps reload issue.
By default, Optimize modifies the content of a webpage only during its initial load. However, dynamic websites (built with tools like AMP, React, Angular, etc.) and single-page apps (SPA) commonly load additional content long after the initial page load. Optimize supports modifying this late-appearing web content via activation events.

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