Re: Re: Async Class

Update: [now we have proposal 1 stage][1] [1]: https://github.com/bmeck/proposal-async-init/issues/1 ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss

Re: Re: Async Class

Claude Pache > class consists not only of its constructor How i see it - seems all think that my idea not bad, but we have semantic hell. My thougth was Class is wrapper for constructor object And Async Class is same wrapper for constructor Promise of object kai zhu >class-factories are good

Re: Async Class

class-factories are good enough. as real-world example, google-puppeteer uses class-factories to promisify its constructors, which are easy-to-reason. if the below Browser/Page classes were also "async", it would be difficult to debug their intent in real-world code -- are their instances

Re: Async Class

> Le 26 août 2019 à 17:11, Dimitrian Nine a écrit : > > Class is just function constructor that return object Although in JS a class is represented by the same object as its constructor, I don’t think it is good to assimilate the concept of JS class and JS constructor. Indeed, a class

Re: Re: Async Class

How it says: "there is no limit to perfection" - [new wrapper][1]. Now it works like more native: ```js class PromiseClass { static async new(test='test'){ this.promise= test; return this;} constructor(...args) { let s = async()=>PromiseClass.new.call(this,...args); return (async r=>await s()

Re: Re: Async Class

>Not a bad idea, but I'd strongly prefer the promise to be returned from new >AsyncClass(...) itself instead This about wrapper? He is just example of how functional can work right now. >I do have a preference: async should decorate the constructor, not the class How i say before: both variants

Re: Re: Async Class

Not a bad idea, but I'd *strongly* prefer the promise to be returned from `new AsyncClass(...)` itself instead. And down that vein, `super` with async classes should also implicitly `await` in its `super` call, setting `this` to the value itself. For sanity reasons, `super` should return a promise

Re: Re: Async Class

Ok so much time has passed. I have learned more js. And created some [wrapper][1] for my idea: Class is just function constructor that return object Async Class is async function constructor that returns promise object. Wrapper code: ```js class PromiseClass { //promisified class static async

Re: Re: Async Class

([Classes][1]): [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes «JavaScript classes, introduced in ECMAScript 2015, are primarily syntactical sugar over JavaScript's existing prototype-based inheritance. The class syntax does not introduce a new object-oriented

Re: Re: Async Class

```js class Test{ constructor(){} async init(){} static async newA(){ let obj = new Test(); obj.init(); return obj }} let t = Test.newA(); class ExtTest extends Test(){ constructor(){ super(); // we cant init here //now we must recreate new/init for ExtTest too }} ``` Or with my proposal we can

Re: Re: Async Class

"why a static factory" And more notes: "return img" - this is cut version In my example you get obj - not image. And my sample was simple. I hope not so long left to class private var + decorators And sample can be then more complex with it: async class Class{ @some_decorator static private

Re: Re: Async Class

"ES classes are about 90% sugar" "ES classes aren't like traditional classes" Yes and i just want to more sugar for them - just simple. ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss

Re: Re: Async Class

I just thought I'd politely point out here that JS isn't a purely OO language (it's even less so class-based OO - ES classes are about 90% sugar over prototype-based inheritance\*). Also, C#, the language that *first* had this kind of syntax, [also doesn't have this][1]. Constructors should be

Re: Re: Async Class

"why a static factory" I answered earlier: <> Yes, you can, but for me more easy to work with classes. And i just want to extend the functionality for work with async - that all. ___

Re: Re: Async Class

I'm still struggling through this thread to see why a static factory method/function with a private constructor/class doesn't suffice for this, or in this case, just procedural functions? (That's what I normally do, [even in ES5][1].) ```js // filter-img.js export async function create(path) {

Re: Re: Async Class

"I think awaitNew MyObject() would fit the thrust of your idea more" For me more good my first version... async class = return Promise(obj) But i can agree with others decisions, if in the end i get: easy way to async new Some people ask me for some more interesting sample... Maybe it can help

Re: Re: Async Class

I think `awaitNew MyObject()` would fit the thrust of your idea more. This would allow `new MyObject()` to still be an instance of the object instead of a promise, even if the constructor is async. It would dispatch the async parts of the constructor to the background instead of awaiting it. e.g.:

Re: Re: Async Class

"Long story short, introducing this feature would slow down new/ Reflect.construct" "since this might suggest it returning a Promise, which it mustn't " Can it help: if async class constructor will be return Promise(obj) and i suggest before use newAsync for that practice? Slow... but how much?

Re: Async Class

Having the constructor return a `Promise` is generally considered bad practice, since it breaks `new X instanceof X`, which in general breaks inheritance. So, for this idea to work, you really shouldn't mark `constructor` as `async` (since this might suggest it returning a `Promise`, which it

Re: Re: Async Class

On Sun, Feb 18, 2018 at 9:07 AM, Naveen Chawla wrote: > > There is no rule that says you must propagate every promise. I never said there was. I said you must handle rejection, or propagate the promise. Or, yes, you can ensure that the promise is never rejected, but that's

Re: Re: Async Class

"new MyObject() would return a promise " I have one idea about it, but not sure good or not... async class and then newAsync Maybe this way more good for someone... ___ es-discuss mailing list es-discuss@mozilla.org

Re: Re: Async Class

In the example, promise rejection can be handled with a try+catch inside `initializeAsync()` itself. But we're deviating from the topic of "async constructor", from which this is separate On Sun, 18 Feb 2018, 2:37 pm Naveen Chawla, wrote: > There is no rule that says you

Re: Re: Async Class

There is no rule that says you must propagate every promise. `initializeAsync` doesn't return anything, so the constructor just kicks off the async process. On Sun, 18 Feb 2018, 2:02 pm T.J. Crowder, wrote: > On Sun, Feb 18, 2018 at 8:27 AM, Naveen Chawla

Re: Re: Async Class

On Sun, Feb 18, 2018 at 8:27 AM, Naveen Chawla wrote: > > Like this: > > ```js > class MyObject{ > constructor(){ > initializeAsync(); > } > > async initializeAsync(){ > await doSomething(); > await doSomethingElse(); > //etc. >

Re: Re: Async Class

Like this: ```js class MyObject{ constructor(){ initializeAsync(); } async initializeAsync(){ await doSomething(); await doSomethingElse(); //etc. } } ``` Of course if you wanted to await at the constructor call level (and await inside the

Re: Re: Async Class

"You can just call an async method from the constructor (without await) - and then let that async method handle all the asynchronicity." Not sure about it - how control? callback? I prefer async/await then. "I think async constructor would make more sense than async class" Maybe: i use it for

Re: Re: Async Class

You can just call an async method from the constructor (without await) - and then let that async method handle all the asynchronicity. Does this satisfy your use case? I think `async constructor` would make more sense than `async class`. Calling `new MyObjectAsync()` would have to return a

Re: Re: Async Class

"It gets ugly(ier) when you want to extend that. :-) " Ok, i get it, but yes i prefer some more sugar like as i suggested before. ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss

Re: Re: Async Class

> I think he means literally returning a promise. That would be the correct assumption. ;-) - Isiah Meadows m...@isiahmeadows.com Looking for web consulting? Or a new website? Send me an email and we can get started. www.isiahmeadows.com On Fri, Feb 16, 2018 at 3:05 AM, T.J. Crowder

Re: Re: Async Class

On Fri, Feb 16, 2018 at 7:51 AM, Dimitrian Nine wrote: > > "Also, note that you can return promises out of the constructor (and I've done it before)" > > Like callback? I think he means literally returning a promise. If you return an object out of the constructor, that

Re: Re: Async Class

"Is an async factory function/method not sufficient to do this?" Maybe, but i think it question similiar to "factory vs class": we can use Сlass now, but why not to extend it to Async then? "Also, note that you can return promises out of the constructor (and I've done it before)" Like callback?

Re: Async Class

Is an async factory function/method not sufficient to do this? Also, note that you *can* return promises out of the constructor (and I've done it before). - Isiah Meadows m...@isiahmeadows.com Looking for web consulting? Or a new website? Send me an email and we can get started.