errata: XFooPrototype = Object.create(HTMLElement.prototype, {
On Sun, Apr 14, 2013 at 12:21 PM, Scott Miles <sjmiles@google.com> wrote:
> >> Alex Russell have been advocating that WebIDL should be allow
> constructor-like interfaces
>
> Absolutely agree. But these are horns of this dilemma.
>
> >> #4 has been accepted for ES6 by all TC39 participants
>
> Yes, I believe this is a timing issue. I am told it will be a long time
> before #4 is practical.
>
> Gecko and Blink have already landed forms of 'document.register', to wit:
>
> Grail-shaped version of document.register:
>
> // use whatever 'class-like' thing you want
>
> class XFoo extends HTMLElement {
> constructor() {
> super();
> this.textContent = "XFoo Ftw";
> }
> }
> document.register('x-foo', XFoo);
>
>
> But since (today!) we cannot extend HTMLElement et al this way, the landed
> implementations use:
>
> // prototype only
>
> XFooPrototype = Object.create(HTMLElement, {
>
> readyCallback: {
> value: function() { // we invented this for constructor-like semantics
>
> super(); // some way of doing this
>
> }
> }
>
> };
>
> // capture the constructor if you care
>
> [XFoo =] document.register('x-foo', {prototype: XFooPrototype);
>
>
> Which for convenience, I like to write this way (but there are footguns):
>
> class XFooThunk extends HTMLElement {
>
> // any constructor here will be ignored
>
> readyCallback() { // we invented this for constructor-like semantics
>
> super();
>
> }
>
> }
>
> // capture the real constructor if you care
>
> [XFoo =] document.register('x-foo', XFooThunk);
>
>
>
> On Sun, Apr 14, 2013 at 12:07 PM, Allen Wirfs-Brock <allen@wirfs-brock.com
> > wrote:
>
>>
>> On Apr 14, 2013, at 11:40 AM, Scott Miles wrote:
>>
>> >> Here are four ways to avoid the subclassing problem for custom elements
>> >> 1) Only allow instances of custome dom elements to be instantiated
>> using document.createElement("x-foo").
>>
>> Wearing web developer hat, I never make elements any other way than
>> createElement (or HTML), so this would be standard operating procedure, so
>> that's all good if we can get buy in.
>>
>>
>> However, I believe that some people such as Alex Russell have been
>> advocating that WebIDL should be allow constructor-like interfaces to
>> support expressions such as:
>> new HTMLWhateverElement()
>>
>> It would be future hostile to make that impossible, but support could
>> reasonably wait for ES6 support.
>>
>>
>> >> 2, 3, 4
>>
>> I believe have been suggested in one form or another, but as I mentioned,
>> were determined to be non-starters for Gecko. I don't think we've heard
>> anything from IE team.
>>
>>
>> Well #4 has been accepted for ES6 by all TC39 participants including
>> Mozilla and Microsoft and is going to happen. The basic scheme was
>> actually suggested a member of the SpiderMonkey team so I'm sure we'll get
>> it worked out for Gecko.
>>
>> Allen
>>
>>
>>
>