Defaulting on Single Page Applications (SPA)
If you’re trying to build a single page application (SPA), you should probably use a tool designed primarily for the job. Site generators focused on performance, shipping low to zero-client-JavaScript (e.g. the one I work on, Eleventy) typically use full page navigations. SPA advocates have rebranded this architecture as a Multi-Page Application (MPA) but fundamentally this is how the web has always operated.
Classic multi-page architecture has a few benefits:
- Better empty-cache performance: your site can render faster.
- As web browsers become more privacy-focused and users spread their browsing across multiple web-capable devices, empty-caches visits are increasingly common.
- Faster sites make more money. Read WPO Stats.
- Search engines use site performance as a search ranking signal, which makes good performance crucial.
- Inclusive and robust by default: You are in full control the minimum requirements necessary to visit your site. You needn’t put any undue burden on the capabilities of the web browser of your visitors. You needn’t place your site behind a “Best Viewed In” browser-compatibility warning. If they can view HTML, they can view your site.
- Energy-efficiency: Lighter pages result in safer long sessions that are more energy efficient and won’t drain your visitors’ laptop or mobile device batteries.
- Privacy-focused: working without client-JavaScript allows visitors full control over their viewing experience. This allows you to create sites that work best in the harsh real world environment of browser extensions, content and ad-blockers; even working with those rare folks that browse with JavaScript disabled.
- Searchable by default: A simpler architecture for server rendered content makes it straightforward for search engines to find you.
- Better defaults for accessibility-focused page navigations, preserving scroll position, forward/back button support, etc.
Single Page Application frameworks in the last few years have pivoted away from client-side rendering to server-rendering and we welcome this improvement. However, the large starting size of client JavaScript bundles customary to SPA persist: Remix (228 kB), Next.js (248 kB), Gatsby (210 kB), and Nuxt (191 kB) source. Notably, these large bundle sizes are only the minimum for a Hello World project and will only grow as your project grows (and as the frameworks grow over time, too).
You can’t JavaScript your way out of an excess-JavaScript problem. These large JavaScript bundles are costly to site performance.
Single Page Application advocates argue these large, costly bundles enable performance gains for future navigations, seamless media playback during transition, and fancy transition animations. While we can debate (and even agree on some of) those points (recognizing also that they will fade into irrelevance as the web platform progresses), take a moment to consider whether or not this trade-off should be made for you as a default.
The data supports the case that Single Page Applications are a bad default for the web too. An analysis of Core Web Vitals across 9.3 million web sites in February 2023 shows that only 26% of sites built using the most popular Single Page Application framework (Next.js) have good Core Web Vitals, far lower than the web at large (40%).
Alternatives
Learn more about alternative approaches that can provide some of the same SPA benefits without the drawbacks:
- Use the View Transitions API to do smooth cross-page animations on navigation.
- Example code using the View Transitions API in an Eleventy project from Vadim Makeev.
- Predictive Prefetching can speed up navigations.
- Prefetching JavaScript libraries:
Trade-offs
- Why I'm not the biggest fan of Single Page Applications by Manuel Matuzović.
- When JavaScript Fails by Jason Godesky.
- Netflix functions without client-side React, and it’s a good thing by Jake Archibald.
- SPA navigation may be slower than MPA navigation, a tweet from Jake Archibald.
- Which has a better FMP? 8.5 MB of HTML or one SPA-rendered Tweet
Originally posted at:
26 Comments
Evan
@zachleat stop being so reasonable.
Zach Leatherman :11ty:
@darth_mall never!! 😅
Jens Oliver Meiert
“You can’t #JavaScript your way out of an excess-JavaScript problem.” ❤️ javascript
DennisL
@zachleat Another good alternative is old-school AJAX/XMLHttpRequest – which, unfortunately isn’t popular anymore. @matuzo
Zach Leatherman :11ty:
@dennisl @matuzo still popular! But also kinda rebranded https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API Fetch API - Web APIs | MDN
Jason Garber
@zachleat 💎 “I’m desperately envious of his beard.”
Evan
@zachleat https://macwright.com/2022/09/15/hacker-news.html Hacker News
Zach Leatherman :11ty:
@darth_mall ha! I also liked this one https://www.youtube.com/watch?v=ga_byUbqvCc Heydon Pickering: Please Disable JavaScript To View This Site
Evan
@zachleat I had an extension installed to disable JS just for his site 😁
passle
@zachleat Lol at the react is only 5KB. Wait until they figure out the size of react-dom
Max Böck
@zachleat API? Are they talking about view transitions? But that doesn't make any sen... Oh right hackernews, my bad.
Scott Jehl
@zachleat exhausting
Zach Leatherman :11ty:
@mxbck The important context here is that SPA <=> website 🫠
Zach Leatherman :11ty:
@scottjehl is my skin hardening or am I just more dead inside 🙃
Max Böck
@zachleat yea right. I guess "Google's propaganda runs deep"
Phil Hawksworth
@zachleat DEEEEEEP sigh.
Evan
@mxbck @zachleat wait, am I missing something?I thought view transitions were a) currently only in Chrome and behind a flag, and b) not available across navigations yet.Is that wrong?
Zach Leatherman :11ty:
@philhawksworth to be fair not all of the comments were bad!
Zach Leatherman :11ty:
@darth_mall @mxbck you’re trying to make sense of nonsense evan 😅the way to make a website available to any browser is to use web standards 👀
Scott Jehl
@zachleat Building simple things the complicated way feels smarter I think. It fools me sometimes too.
Zach Leatherman :11ty:
@scottjehl Well said (and same!)
Cory Dransfeldt :prami:
@zachleat @scottjehl tempted to get this as a tattoo
Alex Russell
@zachleat the parallels between JS-community '23 and Flash community circa '07 are *intense*
Zach Leatherman :11ty:
@slightlyoff you may enjoy this 2023 post from @davatron5000 (I know I did) https://daverupert.com/2023/02/the-case-for-flex-applications/ The case for Flex applications
Evan
@scottjehl @zachleat relatable
Paul Mason
@zachleat I struggle to stay calm when people compare JavaScript file size with image file size. 😖