proposal-import-attributes VS yhtml

Bun introduces the idea of Macros into JavaScript. Macros are a new paradigm that allows optimizations ahead of time just by adding an import attribute.

TypeScript v5.3 builds on its JavaScript foundation by adding import attributes with the usual type safety and tooling benefits inherent to the language. You can follow the TypeScript proposal for import attributes on GitHub.

Yup, in vanilla that's fine, but I'm not sure whether bundlers etc are able to understand import assertions yet, as the spec is still being finalised - for example: the 'assert' keyword has now been officially changed to 'with', but only 'assert' is implemented anywhere at the moment.

Things like HTML (and JSON) imports in ES modules, among other things, have been waiting on some safety signalling mechanics currently named "Import Attributes". Import Attributes are currently in Stage 3 [0].

The basic security story is that browsers never care about file extensions, they care about MIME types. A developer might add an import to a third-party HTML or JSON file somewhere and expect one "safe" behavior, but the third-party could just return a MIME type of "text/javascript" and inject an entire script and the browser is supposed to respect that MIME type.

To keep things safe, browsers want a way to signal that an import is supposed to JSON (or HTML or CSS) rather than JS and error if it gets back something "wrong" from a server request. That's one of the proposed uses for Import Attributes to suggest expected MIME types for non-JS modules in ES module imports.

Unfortunately, there are other proposed uses for Import Attributes (things like including hashes for integrity checks) and so there have been quite a few revisions (and multiple names) for Import Attributes trying to best support as many of the proposed uses as possible, and that has slowed progress on it a lot more than some people would wish.

[0] https://github.com/tc39/proposal-import-attributes

This was an idea that I came up with when thinking about how to handle import styles from './styles.css' with { type: 'css' } in @shgysk8zer0/rollup-import. Import assertions / import attributes are now back to stage 3, but only JSON is actually progressing. So I decided to wait until there's a stable spec.

None of these examples will actually work in a browser, because they are non-standard. Some of you might have correctly spotted that a browser standard exists for two of the imports pointed out in the example, namely the Import Attributes proposal (previously known as Import Assertions), but these imports in their current shape will not work natively in a browser. Many of these non-standard imports exist for good reason; they are very convenient.

import attribute: Import Assertions re-adanced to Stage-3. Proposal for syntax to import ES modules with assertions

The main reason is that they're too low-level to use directly.

They do a lot, but stop just short of being useful without something of a framework on top. I tried hard to use them directly, but found that it was untenable without sensible template interpolation, and without helpers for event binding.

Here's my shot at the smallest possible "framework" atop Web Components that make them workable (and even enjoyable) as an application developer:

https://github.com/dchester/yhtml

It's just ~10 SLOC, admittedly dense, but which make a world of difference in terms of usability. With that in place, now you can write markup in a style not too dissimilar from React or Vue, like...

    ${this.count}

I also sometimes enjoy this approach of starting from absolutely nothing.

Instead of taking the path of starting with DOM manipulation and then going to a framework as necessary, I've kept really trying to make raw web components work, but kept finding that I wanted just a little bit more.

I managed to get the more I wanted -- sensible template interpolation with event binding -- boiled down to a tag function in 481 bytes / 12 lines of (dense) source code, which I feel like is small enough that you can copy/paste it around and not feel to bad about it. It's here if anyone cares to look: https://github.com/dchester/yhtml