Fixes #38

[augonis]

Usage of document.getElementById causes autocomplete to fail to find needed elements if auto-complete is created in javascript or is in the shadowDOM of another element.

This fixes the issue by replacing usage of document.getElementById with querySellector.

[keithamus]

This will break because getRootNode outside of the ShadowDOM returns the element. You'll need to do some more checks. Perhaps it's worth also falling back to light dom if we cannot find the id in the shadowdom?

Suggested change

	const results = this.getRootNode().getElementById(listId)
	const shadowRoot = this.getRootNode()
	let results
	if (shadowRoot instanceof ShadowRoot) {
	results = root.getElementById(listId)
	}
	if (!results) this.ownerDocument.getElementById(listId)

I also think this is a good point to start adding tests that confirm the desired behaviour.

[augonis]

As long as element is connected getRootNode will return either a ShadowRoot or document. As we call it inside connectedCallback, it should be safe. I'll add this.isConnected check in the callback.

To squash the typescript error I'll cast rootNode to Document, as Document and ShadowRoot has no common ancestor.

[keithamus]

That's good clarification, thanks. What do you think about resolving outside of the shadowdom if the element isn't found within the shadowdom?

[augonis]

I think no. auto-complete being inside shadowDOM strongly implies it's being used in the internals of another custom element where encapsulation inside a shadowDOM is the whole point. Better to fail consistently than risk surprising behavior.