Re: [w3c/webcomponents] connectedCallback timing when the document parser creates custom elements (#551)

Not being able to see children in elements at `connectedCallback()` seems like a pretty big hassle when dealing with wrappers that are needed because of lack of support for customized built-in elements.

For example, where before we could write an extension to customize template behavior:

`<template is="fancy-template">fancy stuff</template>`

Now we have to write a wrapper:

`<fancy-template><template>fancy stuff</template></fancy-template>`

And in this wrapper we need to either create a MutationObserver, or wait a microtask, etc. (in addition to any MutationObserve that might have existed on the template's contents). Being able to see children in `connectedCallback()` makes these wrappers that are now required much simpler to write, and still work with `createElement()`.


-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/issues/551#issuecomment-242514089