>> Why do the constructors of component instances run during component
loading?
I'm not sure what you are referring to. What does 'component loading' mean?
>> Why not use standard events rather than callbacks?
This was discussed quite a bit, here is my off-the-cuff response. I may
have to do archaeology to get a better one.
Custom elements can inherit from custom elements. The callbacks are
convenient because (1) there is no question of 'who registers a listener'
(2) I can simply call my 'super' callback (or not) to get inherited
behavior.
IIRC, it is also advantageous for performance and for having control over
the timing these calls.
Scott
On Mon, Apr 15, 2013 at 9:37 AM, John J Barton
<johnjbarton@johnjbarton.com>wrote:
> Why do the constructors of component instances run during component
> loading?
>
> Why not use standard events rather than callbacks?
>
> Thanks,
> jjb
> On Apr 15, 2013 9:04 AM, "Scott Miles" <sjmiles@google.com> wrote:
>
>> Again, 'readyCallback' exists because it's a Bad Idea to run user code
>> during parsing (tree construction). Ready-time is not the same as
>> construct-time.
>>
>> This is the Pinocchio problem:
>> http://lists.w3.org/Archives/Public/public-webapps/2013JanMar/0728.html
>>
>> Scott
>>
>>
>> On Mon, Apr 15, 2013 at 7:45 AM, Rick Waldron <waldron.rick@gmail.com>wrote:
>>
>>>
>>>
>>>
>>> On Mon, Apr 15, 2013 at 8:57 AM, Boris Zbarsky <bzbarsky@mit.edu> wrote:
>>>
>>>> On 4/14/13 5:35 PM, Rick Waldron wrote:
>>>>
>>>>> I have a better understanding of problem caused by these generated
>>>>> HTML*Element constructors: they aren't constructable.
>>>>>
>>>>
>>>> I'd like to understand what's meant here. I have a good understanding
>>>> of how these constructors work in Gecko+SpiderMonkey, but I'm not sure what
>>>> the lacking bit is, other than the fact that they have to create JS objects
>>>> that have special state associated with them, so can't work with an object
>>>> created by the [[Construct]] of a typical function.
>>>>
>>>> Is that what you're referring to, or something else?
>>>
>>>
>>> Sorry, I should've been more specific. What I meant was that:
>>>
>>> new HTMLButtonElement();
>>>
>>> Doesn't construct an HTMLButtonElement, it throws with an "illegal
>>> constructor" in Chrome and "HTMLButtonElement is not a constructor" in
>>> Firefox (I'm sure this is the same across other browsers)
>>>
>>> Which of course means that this is not possible even today:
>>>
>>> function Smile() {
>>> HTMLButtonElement.call(this);
>>> this.textContent = ":)";
>>> }
>>>
>>> Smile.prototype = Object.create(HTMLButtonElement.prototype);
>>>
>>>
>>> Since this doesn't work, the prototype method named "readyCallback" was
>>> invented as a bolt-on stand-in for the actual [[Construct]]
>>>
>>> Hopefully that clarifies?
>>>
>>> Rick
>>>
>>>
>>> PS. A bit of trivial... A long time ago some users requested that
>>> jQuery facilitate a custom constructor; to make this work, John put the
>>> actual constructor code in a prototype method called "init" and set that
>>> method's prototype to jQuery's own prototype. The thing called
>>> "readyCallback" is similar. For those that are interested, I created a gist
>>> with a minimal illustration here: https://gist.github.com/rwldrn/5388544
>>>
>>>
>>>
>>>
>>>
>>>>
>>>>
>>>> -Boris
>>>>
>>>
>>>
>>