[cowboyd]

Context can carry values through a tree, but Bombshell also needs behavior that can be extended within a subtree. Built-in elements, third-party elements, rendering policies, and framework integrations should all be able to participate in semantic operations without subclassing a central object or modifying the core implementation. A node-first API with inherited middleware makes that extension mechanism uniform across every subsystem added later.

Middleware remains correctly composed when a child already has local behavior and an ancestor is extended afterward. That property is essential for independently installed plugins and framework roots: extensions can be assembled in any practical order without duplicating inherited middleware or losing child-specific behavior.

import { createApi } from './core.ts';

const MeasureApi = createApi('measure', {
	measure(_node): number {
		return 0;
	},
});

MeasureApi.around(subtree, {
	measure([node], next) {
		return next(node) + 1;
	},
});

This PR adds createApi(), node-first invocation, and inherited around() middleware to the internal UI core. Tests verify middleware ordering, delegation, subtree inheritance, late ancestor installation, and composition with middleware already installed on descendants.

[pkg-pr-new]

• @examples/basic

  npm i https://pkg.pr.new/bombshell-dev/ui/@clack/ui@18
  

commit: 41100c6

[dreyfus92]

left a few comments, thanks in advance Charles 💜

[dreyfus92]

LGTM, let's wait for other peeps to catch up @cowboyd 😄

[43081j]

Just noting I would like to review before we merge too 👍 I'll take a look tomorrow

[43081j]

let's not, as it just means we're starting with a low bar.

use unknown where you genuinely don't know what the type is, and use never where you're trying to store/accept variable functions.

here's an example

[cowboyd]

closing out in favor of a DOM based substrate. See #37