Question of the Day: What about all this asynchrony?

Logan Smyth loganfsmyth at
Tue Nov 7 19:50:42 UTC 2017

A nit, but that would have to be `for (const move of moves) await
since the `forEach` callback is a normal function.

On Tue, Nov 7, 2017 at 11:47 AM, Naveen Chawla <naveen.chwl at>

> ... that should be `await doMoveAsync()`
> On Wed, 8 Nov 2017 at 01:16 Naveen Chawla <naveen.chwl at> wrote:
>> async functions create a new promise for you upon every invocation, which
>> you resolve via `await`, but that's all invisible in the background. It's
>> basically:
>> async function doMovesAsync(){
>>     moves.forEach(
>>          move=>{
>>               doMoveAsync(); //another async function
>>          }
>>     );
>> }
>> you can do regular programming, in async world. This is why I
>> believe it's more powerful than observables, thereby making them redundant.
>> When I say branching into multiple outputs, I do mean creating new data
>> that leaves the original data untouched.
>> On Tue, 7 Nov 2017 at 20:57 Michael Lewis <mike at> wrote:
>>> Also, if you've made it this far, I think it's worth mentioning that
>>> these async strings are basically all you need for a realtime file system.
>>> File("newFile.ext").append(File("fileA"), File("fileB"),
>>> ...).transpile().save();
>>> // --> automatically watches, all inputs (fileA, fileB, etc), caches
>>> unchanged files, reapplies transforms, writes to file...
>>> Webpack and gulp are basically async plugin systems w/ transforms.
>>> They're just way too complicated.
>>> Simplify all the things.
>>> And while we're at it, why not make a realtime version control system?
>>> Not just for files, but for all the things (any data structure inside the
>>> app).  For example, if we have variable strings, could we enable a history
>>> on it?  Instead of branching onto a separate entity/value, could we branch *within
>>> *the string itself, so that we have an entire *verrsion tree *for any
>>> value?
>>> *What are the fundamental data structures in computer science?*
>>> The Boolean, obviously.  The Integer.  The String.
>>> Why not a realtime boolean?  I suppose that's just a boolean + change
>>> events.  What is a "change event"?  Just an array of functions.  But
>>> JavaScript functions are an abstract concept (compared to processor
>>> instructions).  What do functions look like at the processor level?
>>> They're compiled with all the dependent values, right?  How many processor
>>> ticks does the average line of JavaScript use?
>>> I feel like all languages could boil down to a very small set of
>>> fundamental data structures, and maybe a slightly larger set of specialized
>>> data structures.
>>> What are the different types of circuits in a process?  I understand
>>> (roughly) the basic logic gates, but is there specialized circuitry for
>>> specialized data structures?  What if those fundamental data structures
>>> were optimized at the circuitry level?
>>> What if we can optimize our programs to run as nearly instantly as
>>> possible?  Most scripts are *mostly *instant - at least, there's no
>>> external input.  For any process that's *nearly* instant, couldn't it
>>> actually be instant?  In other words, 1 tick of the processor?  Load up all
>>> the registers with the necessary values, and shine the light down those
>>> transistors/logic gates, so that we arrive at our result, instantly?
>>> I really feel like this is possible.  Like I mentioned earlier, I've
>>> never compiled a lick of code in my life, and have very little
>>> understanding of those things.  But from my sense of JavaScript, it's far
>>> from instant.  How many processor ticks per line of JavaScript code, on
>>> average?
>>> Is anyone still listening?
>>> On Tue, Nov 7, 2017 at 8:47 AM, Michael Lewis <mike at> wrote:
>>>> I'm not experienced in async/await enough to know what "using async
>>>> functions to process [streams]" would look like.
>>>> You would have to create a new promise for every iteration?  Even if
>>>> performance isn't an issue, it just doesn't make sense to me.  It's like,
>>>> you could use `obj.value = "my string"` instead of `var myString = "my
>>>> string"`, and it will work.  And the performance difference is negligible.
>>>> But, it just doesn't make as much sense...
>>>> *Branching vs Mutation*
>>>> The point you bring up regarding "branching the stream into multiple
>>>> outputs" is another fundamental concept in programming (that I'm still
>>>> trying to wrap my head around).  Basically, does an operation (aka a
>>>> method) operate on the original data, or fork/branch, preserving the
>>>> original, and creating a clone to apply the transform to.
>>>> For example, arr.push() manipulates (mutates) the original array, but
>>>> arr.slice() branches, giving you a brand new array, leaving the underlying
>>>> array untouched (immutable).
>>>> This has always been an area of confusion for me.  Which methods are
>>>> mutators, and which are immutable?
>>>> *Async Strings*
>>>> An interesting away to look at all this async stuff, is to consider
>>>> strings, and their operations (methods), in an asynchronous way.  How can a
>>>> string be asynchronous?  Just let it change over time, and broadcast change
>>>> events.
>>>> What if you compose a string with several pieces:
>>>>  asyncParentStr.append(asyncStrA, asyncStrB, asyncStrC).
>>>> Each asyncString can have change events, and will propagate changes to
>>>> anyone depending on it.   asyncStrB.set("new value") will trigger
>>>> asyncParentStr.change() event.
>>>> I feel like this is fundamental functionality that is lacking from
>>>> JavaScript.  Now that we have `const`, shouldn't `var` automatically set up
>>>> change events for that "var"?
>>>> *Async transforms*
>>>> But lets say we do asyncParentStr.append(asyncStrA,
>>>> asyncStrB.replace("hello", "goodbye"), asyncStrC).
>>>> Now we have the question: do we want this .replace() to be a "live"
>>>> transform?  When we asyncStrB.set("hello world"), does it re-apply the
>>>> replace?  I think there are many use cases for both: mutate the original
>>>> asyncStrB, so that all references to this value also exhibit the
>>>> transform.  And also the alternative, the immutable, branching kind of
>>>> transform, where you don't mutate the underlying value, and instead are
>>>> branching.
>>>> This concept is also the core concept of version control: do we
>>>> continue down the same path, or branch off?
>>>> *GUIs will prevail*
>>>> You can try and create different methods ( ._replace() vs .$replace() )
>>>> to represent transform vs branching (I don't know which looks more like
>>>> which).  But, in the end, the GUI will prevail.  Artists can dream about
>>>> how to envision these version trees, and perfect the GUI/experience.  The
>>>> code interface just can't compete with GUI, in the long run.
>>>> I suppose, its necessarily true that the API preceeds the GUI.
>>>> API before GUI, but GUI all the things.  That's my new motto.
>>>> *What if variables were automatically async, and referential? *(As
>>>> opposed to `const` that could be the immutable flavor)
>>>> var str = "hello world";
>>>> str.replace("hello", "goodbye"); // transforms `str` var "in place"
>>>> log(str) // "goodbye world"
>>>> str = "hello cruel world"; // transform is reapplied
>>>> log(str) // "goodbye cruel world"
>>>> This will never happen, but it shows the fundamental difference in
>>>> logic.  Both are logical/useful...
>>>> On Tue, Nov 7, 2017 at 8:08 AM, Naveen Chawla <naveen.chwl at>
>>>> wrote:
>>>>> For me the future is async functions (the present actually). I asked a
>>>>> question about possible support for async streams / observables here:
>>>>> and I realized that my
>>>>> use case was much better served by just using async functions to process
>>>>> each input value in the stream.
>>>>> I think using async functions is much more powerful than
>>>>> "observables", since it allows you to easily branch the stream off into
>>>>> multiple outputs etc. Using Promise.all etc. is also trivial to use where
>>>>> desired, etc.
>>>>> Furthermore, async functions allow while/for loops that include other
>>>>> async function calls, and this looks like programming with regular
>>>>> functions, so it's trivial to set up asynchronous iteration, and/or
>>>>> infinite event processing, etc., even without the new "async iteration"
>>>>> proposal.
>>>>> On Tue, 7 Nov 2017 at 17:25 Michael Lewis <mike at> wrote:
>>>>>> The email wasn't about my kids, and you don't have to read it (duh).
>>>>>> If your time is so valuable, maybe you shouldn't be picking fights with
>>>>>> rambling parents.
>>>>>> Where is the list of approved topics?
>>>>>> On Tue, Nov 7, 2017 at 5:44 AM, Bob Myers <rtm at> wrote:
>>>>>>> I'm confused. You don't have time to read "The General Theory of
>>>>>>> Reactivity", yet (1) you have time to write this long, rambling email about
>>>>>>> your kids, and (2) expect people on this mailing list to spend their
>>>>>>> valuable time reading it?
>>>>>>> Please stay on topic for the list.
>>>>>>> Bob
>>>>>>> On Tue, Nov 7, 2017 at 4:48 PM, Michael Lewis <mike at>
>>>>>>> wrote:
>>>>>>>> Good morning JavaScript world,
>>>>>>>> Maybe I'll start my mornings with a cup of coffee, and a discussion
>>>>>>>> prompt.  We'll see how long it lasts.  It's 4:39am.  I live in Aurora,
>>>>>>>> Illinois, about an hour outside of Chicago.  My kids will wake up in an
>>>>>>>> hour or two, so I don't have long, and should be working on my framework
>>>>>>>> anyway.
>>>>>>>> *So much asynchrony*
>>>>>>>> There are callbacks, promises, async/await.  We have streams in
>>>>>>>> node.js.  There are libraries like RxJS for Observables (that are basically
>>>>>>>> streams?).
>>>>>>>> What's the end game?  What will our children's children be learning
>>>>>>>> in 100 years?  Let's reduce these pieces, distilling them into their
>>>>>>>> simplest components.
>>>>>>>> This <> is an
>>>>>>>> interesting thread (from es-discuss) regarding asynchrony, which references
>>>>>>>> Kris Kowal's General Theory of Reactivity
>>>>>>>> <>, which is too long for me to
>>>>>>>> dig into at this point in my life.
>>>>>>>> The disappointing part, is that this community (who has mastered
>>>>>>>> asynchrony) doesn't feel like there are any shortcomings, and so we
>>>>>>>> continue onward without fixing the mess.
>>>>>>>> Oh, and generators?  I don't fully understand these things.  Do
>>>>>>>> they work with promises?  Can you use a generator to process a stream?  How
>>>>>>>> do generators work with or compare to async/await?  Who knows...
>>>>>>>> I think it's safe to say that asynchrony is a confusing mess.  *But
>>>>>>>> it shouldn't be.   *The concept of "do it now" or "do it later" is
>>>>>>>> as easy as 123.
>>>>>>>> Recently, I read through Jake Archibald's JavaScript Promises: an
>>>>>>>> Introduction
>>>>>>>> <>.
>>>>>>>> I really enjoy Jake Archibald's writing.  He makes JavaScript less boring.
>>>>>>>> But wow, understanding promises in their full depth is really complicated.
>>>>>>>> Sure, a simple promise is more or less a callback, easy peasy.  But once
>>>>>>>> you start composing parallel and series tasks, add error handling, and try
>>>>>>>> to understand the control flow - it's a lot.
>>>>>>>> I feel like Promises could automatically *render a diagram *when
>>>>>>>> using them.  In Jake's very practical example (request a list of chapters,
>>>>>>>> load all chapters in parallel, then append them to the page in order)
>>>>>>>> there's a lot going on, to say the least.  Wouldn't it be nice to see a
>>>>>>>> diagram of these tasks?  A timeline maybe?
>>>>>>>> Imagine debugging a complex sequence of async actions.  And you
>>>>>>>> have no idea which piece is failing.  Using the console to log values, and
>>>>>>>> trying to step through the code with the debugger are two of your basic
>>>>>>>> approaches.  But honestly, neither of these really *show *you
>>>>>>>> what's going on.
>>>>>>>> Chrome Dev Tools has an awesome timeline GUI.  I've spent an hour
>>>>>>>> here or there tinkering with it, but can't make sense of a lot of it.
>>>>>>>> There are 100's if not 1000's of very generic blocks that show up on the
>>>>>>>> timeline, that don't clearly identify what they are.  And I don't believe
>>>>>>>> there's any way to visualize promises on this timeline.
>>>>>>>> *The problem with Promises*
>>>>>>>> I want to create a file system framework for node.  I'd like to
>>>>>>>> make watching the files for changes a default feature.  The problem with
>>>>>>>> promises, is that you can't re-resolve them.
>>>>>>>> So I'm basically left with streams, or plain old callbacks.  Or
>>>>>>>> trying to recreate the promises every time they resolve...
>>>>>>>> What's the end game?  100 years from now?
>>>>>>>> Frankly, this is the most important question.  I feel like if we
>>>>>>>> take a step back, and try to solve these problems for the long term, we'd
>>>>>>>> be better off.
>>>>>>>> And so, it's 5:15.  Well done, Michael.  Well done.
>>>>>>>> *The Future*
>>>>>>>> If anyone has made it this far, I'm going to tell you a quick
>>>>>>>> summary of my plan:
>>>>>>>>    1. make an ultra-simple web framework (almost done?)
>>>>>>>>    2. use that framework to make a CMS to kill WordPress
>>>>>>>>    3. turn that CMS into a web OS that does everything a real OS
>>>>>>>>    can do, only better
>>>>>>>>    4. turn that web OS into a real, bare metal OS
>>>>>>>>    5. make lots of amazing (useful) software (like photoshop,
>>>>>>>>    blender, after effects, CAD, etc)
>>>>>>>> Software development is sluggish.  Most software is painful to
>>>>>>>> use.  Windows, Photoshop/Illustrator, many websites...  Open source
>>>>>>>> software doesn't get the funding/momentum it needs to really kill these
>>>>>>>> proprietary alternatives.  We need to change that.  I'm going to change
>>>>>>>> that.
>>>>>>>> Stay tuned.
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