[Proposal] New syntax for lazy getters

[Michał Wadas]

Yes, something is getting done about decorators.
https://github.com/tc39/agendas/pull/398

On Tue, Jun 12, 2018 at 4:27 PM, Andrea Giammarchi <
andrea.giammarchi at gmail.com> wrote:

> To me decorators are the answer to pretty much everything but for the last
> year I've seen zero progress on what seems to be a forever Stage 2
> proposal: https://github.com/tc39/proposals#stage-2
>
> Is there anything anyone can do to speed up adoption/implementation of
> that proposal?
>
> On Tue, Jun 12, 2018 at 4:24 PM, Augusto Moura <augusto.borgesm at gmail.com>
> wrote:
>
>> I don't think a new keyword is the right path here. For classes lazy
>> fields can easily be implemented via decorators in the last proposal[1]
>> (also, Groovy has previous work implementing a `@Lazy` annotation[2] with
>> AST transformations for the same use case). In code something like:
>> ``` js
>> const lazy = (fieldMetadata) => {
>>   // change the field value in descriptor to a lazy factory
>> };
>>
>> class Foo {
>>
>>   @lazy bar = slowCalculation();
>>
>>   @lazy statements = (() => {
>>      if (this.bar > 0) {
>>        return fooify();
>>      } else {
>>        return barify();
>>      }
>>   }());
>>
>> }
>> ```
>>
>> What it's doesn't cover (and in my opinion should be the focus of a new
>> proposal) is Decorators for literal objects. Something like the code below
>> is yet not proposed:
>>
>> ``` js
>> const foo = {
>>   @lazy bar: 3,
>> };
>> ```
>>
>> I didn't made a deep search in ESDiscuss history but I remember this
>> feature being mentioned sometime ago.
>>
>> [1]: https://github.com/tc39/proposal-decorators
>> [2]: http://groovy-lang.org/metaprogramming.html#xform-Lazy
>> --
>> Augusto Moura
>>
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>>
>>
>
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