On June 12, 2018 9:44:31 AM GMT+02:00, Andrea Giammarchi
<andrea.giammar...@gmail.com> wrote:
>My 2 cents,
>I use lazy getters since about ever and I'd love to have such syntax in
>place but I think there is room for some improvement / simplification
>in
>terms of syntax.
Yeah I find this better.
Also fixes the this questions by unambiguously setting it to the instance.
>*## Keep it getish*
>
>From parsing perspective, introducing `lazy tail()` seems way simpler
>than
>introducing `lazy tail:` for the simple reason that everything that can
>parse `get tail()` and `set tail()` is in place already in every
>engine. I
>don't write them but I'm sure having an extra keyboard to catch
>shouldn't
>be crazy complicated.
>
>*## class compatible*
>
>because you used `delete this.tail` and mentioned functional
>programming,
>I'd like to underline ES doesn't force anyone to one programming style
>or
>another. That means new syntax should play nicely with classes too, and
>in
>this case the proposal doesn't seem to address that because of the
>direct
>value mutation, as generic property, and the removal of that property
>from
>the object, something not needed if inherited.
>
>My variant would do the same, except it would keep the value an
>accessor:
>
>```js
>const take = (n, xs) => n === 0 ? null : xs && {
> head: xs.head,
> lazy tail() {
> return Object.defineProperty(this, 'tail', {
> configurable: false,
Why enforcing configurable false? When you use get x() / set x() syntax, it
leaves the thing configurable true. I feel it is more consistent to have the
replaced getter copy configurable from existing status quo, that is, what is
actual configurable of this.tail.
And of course, Object.defineProperty family needs a way to create this, I think
{get: getterFn, lazy: true, …} could work.
Herby
> get: (value =>
> // still a getter
> () => value
> )(
> // executed once
> take(n - 1, xs.tail)
> )
> }).tail;
> }
>};
>```
>
>This would keep initial accessor configuration, in terms of
>enumerability,
>but it will freeze its value forever and, on top of that, this will
>play
>already well with current valid ES2015 classes syntax.
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