Updates on 2022/3/17

I had to write a DOM TreeWalker today for a personal project that was written in Oak, and it's surprising how pleasant it was to write. I'd say it was the same or better than using the same DOM API from JavaScript.

// headingsList takes some container <div> and returns a list of all headings
// within that section of the page, in order
fn headingsList(div) {
	walker := document.createTreeWalker(
		div
		NodeFilter.SHOW_ELEMENT
		{
			acceptNode: fn(el) if el.tagName {
				'H1', 'H2', 'H3', 'H4', 'H5', 'H6' -> NodeFilter.FILTER_ACCEPT
				_ -> NodeFilter.FILTER_SKIP
			}
		}
	)

	headings := []
	with loop() fn(_, break) if el := walker.nextNode() {
		? -> break(headings)
		_ -> headings << {
			level: int(el.tagName.1)
			text: el.textContent
		}
	}
}

This is mostly due to two things, I think:

1. The recently finalized std.loop API is really nice for generic unbounded loops.
2. This semi-recent change to oak build --web codegen made JS methods very nice to call from Oak.