yhtml VS uibuilder

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

This looks bad. I see custom syntax, and JavaScript embedded into HTML in a way that cannot be syntax-checked at build time.

If you want a lightweight framework check out UIBuilder instead: https://github.com/wisercoder/uibuilder

Same JSX syntax as React, but this lib is very simple -- just over 200 lines of source code.

If you don't need Virtual DOM then Web Components are a great idea for building reusable components that work with all frameworks, including React. You can even use JSX to build Web Components: https://github.com/wisercoder/uibuilder