single-spa VS import-maps

Single-SPA Framework - One of the most popular choices. It has a large community behind it and offers robust routing and lifecycle management for microapps. Ref - https://single-spa.js.org/

Joel Denning is the visionary behind single-spa, boasting profound insights into the true mechanics of the web and is, in my view, a pioneer in micro frontend architecture. I highly recommend checking the single-spa website and his YouTube channel. While the videos might appear dated at first glance, rest assured, Joel is ahead of his time, and the content remains incredibly relevant today.

You got me curious and I found that single spa is something new to me - if I read https://github.com/single-spa/single-spa then I reckon you can use Svelte(Kit) in such framework - like you can use angular etc

I’ve actually done that “web components as the interoperability layer”!

It was this old angular 1.8 app with new features being written in angular-hybrid-ized angular 8. Ripping out angular-hybrid and separating the angular 1.8 routes from the modern angular routes was difficult, but now they were totally separate.

The only thing linking them together was an object with some RXJS streams in it for state, and a little in-house wrapper “app” who just loaded one component or another depending on the URL and a hash of routes for config. (I’d probably use SingleSPA [1] now. Same thing really.)

We could deploy them separately since the build just ends up being another JS file somewhere that just gets included with a script tag at runtime. No version bumping! No big mega build!

We started replacing the remaining “old” routes 1 by 1 with a “new” counter part. That was the easiest part, and went at a pace devs were comfortable with (fast enough) and business folk could tolerate. (modular enough to not HAVE to be done all at once)

Last I checked, the angular 1.8 stuff is gone years ago. :)

[1] https://single-spa.js.org/

Module Federation is not the unique solution, for example single-spa

You may want to look into using single-spa to run Vue 2 and Vue 3 side by side while you're migrating. Once your app is fully converted, you can stop using single-spa

Single-SPA and module federation are potent tools for building scalable micro-frontends. Single-spa provides a framework for building a modular front-end application. It allows lazy loading of micro-frontends, which helps improve the application's performance. In contrast, module federation enables communication and dependency sharing between different micro-frontends. It reduces code duplication, which can help with scaling an application.

Since micro-frontend allows us to develop applications individually, this also means you can use different frameworks and libraries together to develop each section of this application. Of course, this will have some advantages and disadvantages. If you are using different technologies to serve different parts of the application, it won't be so easy to move developers within teams. However, the door is open, and if you want to do something like that, you could use something like Single SPA, or some other, to help you organize and connect the different technologies into a larger application.

Long time huge fan of JS. I appreciate your calling out the multi-paradigm aspect; having these first class functions & prototype based inheritance has been so flexible.

TC39 has done a great job shaping the language over the years. New capabilities are usually well thought out & integrate well. Async await has been amazing.

The one major miss that makes me so sad and frustrated is modules; js has gotten better everywhere except it's near requirement for build tooling. Being able to throw some scripts on a page and go is still an unparalleled experience in the world, is so direct & tactile an experience. EcmaScript Modules was supposed to improve things, help get us back, but imports using url specifiers made the whole thing non-modular, was a miss. We're still tangled & torn. Import-maps has finally fixed but it's no where near as straightforward, and it still doesn't work in workers, which leaves us infuriatingly shirt of where the past was. https://github.com/WICG/import-maps/issues/2

makes sure your app is getting the download it expects. Adoption is probably pretty minimal though. https://developer.mozilla.org/en-US/docs/Web/Security/Subres...

I think the big thing making this unlikely though is that very few folks use cdns these days. We designed ESM as a module system for the language, but then took a good fraction of a decade to build import-maps, to let us actually use modules in a modular way. Good news, we can finally use modules modularly! https://caniuse.com/import-maps

Bad news? Oh import-maps only works for the simplest case. Doesn't work in webworkers/service workers. https://github.com/WICG/import-maps/issues/2

The point is that single page apps almost always are bundled together, as using CDNs hasn't even been technically possible.

Also, CDNs are kind of somewhat pointless, now that http caches are partitioned by origin (for security reasons). They might have better anycast infrastructure to get the content out faster, but without the caching there's no inherent advantage. The user will download the same jquery file again in each site they go to, no already having it cached anymore. Bah humbug!

https://github.com/WICG/import-maps/issues/2

Bare specifiers has been the tragedy of ESM. Nice module syntax... that is utterly u deoyable & which has had to have awful de-modularizing specifiers hard-coded into each file to make it work. Abominable sin to introduce "modules" to JS/es2015 then spend a decade dragging everyone along with no story for how to have modular modules.

Import-maps are like "here" to fix this on the web... finally... except they only are shipping to the happiest sunniest easiest case, with Web Workers being totally shit out of luck in spite of some very simple straightforward suggested paths forward. https://github.com/WICG/import-maps/issues/2

I think Deno is making pretty good tradeoffs along the way here. This looks like package.json at surface level, but there is a nightmare of complexity under the surface. Typescript, ESM, cjs all have various pressures they create & in Node it's just incredibly tight & tense dealing with packaging, where-as Deno's happy path of Typescript first does not slowly tatters one over time. It really has been super pleasant being free of the previous world, and having something much more web-platform centric, more intented, with less assembly & less building, and more doing the actual coding.

I really hope import-maps eventually get broader support. Maybe this long-dwelling webworker issue should be brought up with WinterCG.

Import maps proposal

The concept of Import Maps was born in 2018 and made its long way until it was declared a new web standard implemented by Chrome in 2021 and some other browsers.

For package managers, you can use something like import maps to let the user specify which path points to what package, and resolve it properly.

Huh. I was about to complain that this breaks with web standards, but apparently it's being proposed as a standard feature: https://github.com/WICG/import-maps

Interesting!