Any news about the `<module>` element?

John Barton johnjbarton at google.com
Sun Dec 21 09:02:54 PST 2014


Couldn't the <module> tag be restricted to be the last tag inside <html>?
Then we don't need them to be async to avoid blocking rendering and the
declarative order would more closely match the semantics.  Multiple tags
could be loaded in parallel and sequenced on execution.

jjb

On Sat, Dec 20, 2014 at 3:59 PM, Allen Wirfs-Brock <allen at wirfs-brock.com>
wrote:

>
> On Dec 20, 2014, at 2:02 PM, Caridy Patino wrote:
>
> John, think of <script defer src="mod.js"></script>.
>
> For <script type=module>, async is implicit.
>
>
> What if you have a series of modules that need to be evaluated in
> sequential order?  (Remember, that a module with no imports is the module
> worlds  equivalent to a simple  sequential script.).  eg:
>
> <script type="module">
>    window.sequence = 10;
>    console.log(window.sequence);
> /script>
> script type="module">
>    console.log(" should be 11: " + ++window.sequence);
> </script>
> <script type="module">
>    console.log(" shoud be 12: " + ++window.sequence);
> </script>
>
> Allen
>
>
>
>
>
>
>
>
>
>
> Sent from my iPhone
>
> On Dec 20, 2014, at 3:01 PM, John Barton <johnjbarton at google.com> wrote:
>
>
>
> On Sat, Dec 20, 2014 at 10:54 AM, Matthew Robb <matthewwrobb at gmail.com>
> wrote:
>
>>
>> On Sat, Dec 20, 2014 at 1:50 PM, Caridy Patino <caridy at gmail.com> wrote:
>>
>>> what make you think this proposal implies blocking?
>>
>>
>> ​I think he was reading your examples using "require()" and thinking you
>> were suggesting that the semantics would match.​
>>
>
> Indeed that is what I was thinking.
>
> A non-blocking <module> tag is a poor match to HTML, a declarative
> language where order of tags means order of parsing and rendering. Giving
> up this fundamental characteristic of HTML, in the long-shot effort to
> improve the apparent load time for some amateur Web sites, has become
> dogmatic so I suppose there is no value in discussing it.
>
> A non-blocking <module> tag would also prevent experienced developers from
> controlling rendering through JS action. That means they will need to use
> <script> tags which we'd like to deprecate or we'd have to have a blocking
> form of <module>.  We'll probably end up with the latter choice.
>
> On the node side, require() is curiously synchronous given node's heavy
> emphasis on asynchronous IO. As with the browser <script> tag, the
> synchronous require() is the best choice for simplicity.  But the
> synchronous semantics prevents optimizations on both platforms. An
> asynchronous root-module loading API in a next generation system opens new
> opportunities.  I hope and expect we'll end up with an async option on node.
>
> On balance I think a non-blocking <module> tag with optional blocking is
> reasonable.
>
> However, the description of the browser loading as "require()" within a
> asynchronous <module> tag is really a complete departure from all the
> previous discussions.  A system based on require() is not statically
> analyzable. I could go on, but really a shift to this extreme seems so
> unlikely that there must be some misunderstanding.  Rather I assume that
> the content of the <module> tag will be ES6 code as we know it now and that
> we will have an additional dynamic loading API that will be asynchronous
> much like we had earlier this year.  Exactly the same solution would work
> in node.
>
> In other words, <script> and require() would not be used in future code,
> an async API would be available for root loading, and most developers most
> of the time would write synchronous code manipulating modules contents.  If
> we are not heading in this direction I hope there will be more discussions
> in public.
>
> jjb
>
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