RE: The key custom elements question: custom constructors?

From: Travis Leithead [mailto:travis.leithead@microsoft.com]

> I've discussed this issue with some of Edge's key parser developers.

Awesome; thank you for doing that!

> I believe to be the most straightforward approach that most closely matches how the platform itself works

Thanks, it's helpful to get this non-implementation-focused reasoning out in the open.

What are your responses to Olli's concerns about how this is hard to spec properly? I.e. "no one ever managed to spec MutationEvents properly, and running author code during cloneNode(true) is at least as hard problem to solve." Are you concerned about interop? It sounds like it's technically feasible for you, but do you think it will be technically feasible in a way that is interoperable? (I realize that's a hard question to answer.)

> For example, in parsing, I would expect that the callout happens after initial instance creation, but before the target node is attached to the DOM tree by the parser.

Can you expand on this more? In particular I am confused on how "initial instance creation" can happen without calling the constructor.

> I am sympathetic to this concern, but have my own reservations about the proto-swizzle technique.

I think this is not the correct positioning for this question. There are two independent questions: is it OK to run author code during parsing and cloning? And separately, is there utility to be gained from proto-swizzling? You can imagine (at least) four solutions for this 2x2 grid of yes/no responses. In this particular thread I really want to focus on the former question since it is foundational.

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It sounds like so far we have:

- Mozilla against running author code during these times
- Microsoft for running author code during these times, but sympathetic to concerns in the opposite direction

Is this correct so far?

I suppose I should also note

- Google against running author code during these times, based on investigation by Dominic (with an "i") into the complexity it would add to the platform/event loop/etc. (I believe the exact phrase "MutationEvents all over again" was used.)

Received on Thursday, 16 July 2015 05:31:14 UTC