How to determine when to do the manual allocation when using Imperative Shadow DOM Distribution API

[caridy]

Proposal: https://github.com/w3c/webcomponents/blob/gh-pages/proposals/Imperative-Shadow-DOM-Distribution-API.md

@hayatoito, the proposal is looking good from the perspective of doing the manual allocation, but it is not providing enough information, or end-to-end examples.

My main concern is that with manual, no auto allocation/slotting will be done, which probably mean that you cannot use slotchange event to observe changes in your slots. The question is, how will the developer know when to do the manual allocation? And the answer cannot be: "just use mutation observer".

I think from our side, we will like to have a reliable signal for changes on the light tree so the allocation can happen accordingly. The most dummy example could be:

<fancy-menu>
     <menu-item>one</menu-item>
     <menu-item>two</menu-item>
</fancy-menu>

When adding a new menu item (e.g.: myFancyMenuElement.appendChild(menuItemThreeElement)), we should be able to detect that operation, and take care of the manual slotting on the spot.

/cc @diervo

[annevk]

Could you please mention this in whatwg/html#3534 instead. Seems good to keep discussion a bit centralized for now.

[caridy]

too many notifications to keep up with everything :), will post there!