How NextJS REALLY Works

Summary

This video clarifies the difference between server-side rendered (SSR) frameworks like Next.js and Remix and traditional single-page applications (SPAs) like Create React App. The key distinction lies in how initial HTML is loaded: SSR frameworks provide correct HTML from the start, while SPAs load incomplete HTML first and fill it in later with JavaScript. The video explains how Next.js offers the benefits of correct HTML on first load, faster performance, better SEO, and enhanced developer control. It emphasizes that Next.js is a single-page app framework with server-side capabilities, making it ideal for modern React applications.

Takeaways

• 😀 Next.js and Remix generate the correct HTML on the server for the first load, improving initial rendering and SEO.
• 😀 Single-page applications (SPAs) like Create React App (CRA) load incorrect HTML initially, requiring JavaScript to fetch and render the content, which takes longer.
• 😀 The main difference between Next.js/Remix and SPA frameworks is how they handle initial HTML—correct for Next.js/Remix, incorrect for SPAs like CRA.
• 😀 Next.js and Remix are still single-page app frameworks but with the added benefit of server-side rendering (SSR) for better first-page performance.
• 😀 Next.js and Remix allow for dynamic data fetching and generation of pages on the server, which can make the app more performant and SEO-friendly.
• 😀 The key benefit of SSR frameworks like Next.js is faster load times, as they serve correct HTML from the server rather than relying on client-side rendering to fix it.
• 😀 Next.js and Remix are not alternatives to React but frameworks that enhance React by enabling server-side rendering without sacrificing client-side interactivity.
• 😀 Once the page loads, Next.js becomes a standard React app on the client, maintaining a single-page application structure.
• 😀 Developers may regret not using server-side rendering (SSR) later when they need dynamic content generation or better control over HTML delivery.
• 😀 Using server-side rendering in Next.js/Remix makes development easier, even if you don’t need it immediately, as it simplifies SEO and dynamic content handling.

Q & A

What is the main difference between Next.js/Remix and traditional SPAs like Create React App?

The main difference lies in how the initial HTML is loaded. In Next.js and Remix, the HTML is generated server-side, ensuring it's correct when it reaches the client. In contrast, SPAs like Create React App generate incorrect HTML initially and rely on JavaScript to render the content, which can lead to performance issues.

Why does the initial HTML in traditional SPAs like Create React App load incorrectly?

In traditional SPAs, the initial HTML is not fully rendered. The page loads with placeholder content, and the JavaScript is responsible for fetching the data and rendering the correct content afterward. This process can be slower and result in incomplete or incorrect HTML until the JavaScript finishes loading.

What are the advantages of server-side rendering (SSR) in Next.js and Remix?

SSR allows the HTML to be generated on the server and delivered to the client with correct content. This improves SEO, reduces the time to the first meaningful paint, and ensures that the user sees the complete page faster. It also prevents issues that arise when JavaScript takes time to load and fetch the necessary data.

Does using Next.js or Remix make a page load slower compared to SPAs?

Not necessarily. The HTML generated by Next.js or Remix can be served just as fast as static HTML generated by a Create React App. The difference comes when dynamic content is involved. Server-side rendering in Next.js or Remix can provide the correct content right away, while an SPA may require additional time to fetch data after the page loads.

Can Next.js and Remix be used as single-page apps?

Yes, Next.js and Remix are fundamentally single-page app frameworks that support features like server-side rendering and static site generation. While they enable server-side content generation, they still operate like SPAs once the first page is loaded, providing a seamless experience for the user.

How does Next.js handle dynamic content, such as a user's profile data or view count?

In Next.js, dynamic content like user data can be fetched server-side during the page rendering process. This ensures that the user sees the correct content immediately. If needed, Next.js can block the page rendering until the necessary data is fetched, while traditional SPAs may need multiple fetches after the page is loaded.

What happens if I don't need dynamic content and want a static page with Next.js or Remix?

Next.js and Remix provide an easy way to generate static pages at build time, similar to how traditional SPAs work. You can avoid using server-side rendering if you don't need dynamic content, which allows you to build a static, faster page with the benefits of these frameworks' tools.

What is the benefit of using server-side rendering (SSR) for SEO?

Server-side rendering ensures that the HTML delivered to search engine bots is correct and fully populated with the right content, improving SEO. This is crucial for visibility in search results, as search engines can index pages faster when they don't have to wait for JavaScript to execute and fetch the content.

Why is server-side rendering important for long-term projects?

As projects evolve, there is often a need for dynamic content, accurate metadata, and improved SEO. Without SSR, developers may face challenges in meeting these requirements, leading to workarounds that can be inefficient. Server-side rendering with frameworks like Next.js or Remix ensures the content is correct and optimized from the start, saving time and effort in the long run.

What is the key benefit of using Next.js for building single-page applications?

Next.js offers the ability to build single-page applications with correct HTML generated server-side, which is advantageous for both performance and SEO. This provides the flexibility of a traditional SPA while offering better initial load times and search engine optimization.