[Silhouette]

This is the direct effect of high levels of backwards compatability. You can't change APIs; you have to create new APIs and then deprecate previous APIs.

I don't see how that follows at all. You can't make breaking changes to APIs, but it's fine to extend them or even expose different levels of abstraction as long as the underlying model you're using stays consistent and you provide suitable defaults where necessary.

If you don't need to do any work to something it has zero cost.

This is tautological, but if we're talking about a typical web application then you are working with that code, every time you make a new build. It might sit there as an untouched black box for a while, but if it has any kind of external dependencies or it relies on anything that could change about the language, platform or other parts of your own code, then there is always a risk that it will later break, and then you'd better hope you have someone around who still knows how to fix it.

This isn't mainstream yet. Until very recently the majority of companies were targetting IE 11.

You've made several claims like that, but in the absence of data there's no way to know whether you're correct. For example, preset-env has been in production for 3+ years now and had an extended beta/RC phase before that. It's true that it defaults to ES5 if you don't configure it, but the Babel docs explicitly recommend that you do, and it is literally a one-line change in your package.json to do something more modern and efficient based on Browserslist unless you genuinely need that degree of backward compatibility.

Of course, in some cases, even quite recently, you did need that. A relatively small proportion of business customers stuck in the IE11 era could still represent significant revenue at risk if you dropped support. But it will take more than an unsupported assertion to convince me that this has been the norm for most web development for quite some time. At one of my businesses, we've had literally no-one using IE11 visit a B2C web app for years. At another that mostly does outsourced development work, we've excluded IE support contractually for a long time and no client of any size has pushed back in years. There must be many thousands of other small businesses out there like mine, and I have to assume that they have senior devs who sometimes read the docs for the tools they use too.

OK, yeah, I'm not seeing this at all.

I think that's because you persist in interpreting my comments as being about JS itself, when I've tried repeatedly to emphasize that it is the culture and surrounding ecosystem that are the bigger problems. I'm not talking about the technical committees defining the language. I'm talking about the developer experience of using it in production.

On that score, I stand by my earlier comments. After many years of programming professionally, using many different languages, I have yet to find any more flaky ecosystem than JavaScript's other than the deliberately fast-paced world of Haskell. Nothing else even comes close for how much wasted effort I've seen over the years just keeping all the plates spinning so nothing falls off and breaks.

But most of the products these people create are also being replaced every 2 years so it's not as big an issue as you think it is.

Yes, I understand the commercial argument. The bizarre economics in the web dev industry sometimes make throwing entire projects out and rewriting every 2 years affordable. That doesn't mean it's not a horribly unstable environment, which was the original point of contention, nor that disregarding traditional wisdom about the dangers of big rewrites isn't a bad idea. It just means parts of the industry are so rich that they can afford to have a toxic culture where quality is a second-class citizen and the only answer to producing so much unmaintainable junk is exactly what you said. It's much nicer working in other parts of the software industry where what you're producing is expected to work and to last, but sadly it doesn't always pay as well.

It has testing frameworks, it has automated code formatters, it has linters...

And these kinds of things are advanced tooling, in your view? We had those in our IDEs for building desktop software back in the last century. Except they were automating rewriting millions of lines of code on 2000-era PCs, not 10,000 lines of code on 2020-era PCs.

I'm not sure what other popular programming language ecosystems you think don't have these kinds of tools today or have tools significantly worse. But in web development, TS is the current hotness because the developers finally realised that explicit typing is helpful for building and maintaining more than small systems, and not so long ago build tools adopting tree shaking was being heralded as a great advance for reducing the size of builds, and before that we got the radical new concept of a module import/export system so you could write code in more than one file without jumping through crazy hoops, and before that we discovered that immediate mode UIs and declarative specs are a thing. All of these ideas were well known and widely used elsewhere in the programming world much, much earlier.

Are you trying to tell me that a breaking change that was so bad that it took almost a decade for the community to complete is something that we should aspire to?

It took that long because that backward compatibility and stability we've been talking about meant a lot of older projects didn't need to move any sooner. And yes, having a platform where you can write code and it keeps working and the ecosystem still positively supports it for another decade is definitely something we should aspire to.

Generally not in the major libraries (React, etc).

Don't tell that to anyone who uses React Router. Or who builds their app with Webpack. Or Babel, as you mentioned. And again, it's important to note that you only said backward compatibility here. If we're talking about the broader concept of stability then you also have to include high profile libraries like Moment giving way to more modern alternatives because although they still work, they don't lend themselves to modern programming styles or play so nicely with other tools.

These comments are getting long and I suspect we may have to agree to disagree on some of this, but if you haven't worked much on software in other parts of the industry, I encourage you to look at what is considered the norm and acceptable practice in fields where better quality and greater longevity are more highly valued. If we built security libraries or the embedded software controlling industrial machinery the way a lot of online companies build their web apps, we'd be lucky to survive the night.

[lhnz]

I'm trying to respond in good faith, even though I feel you unnecessarily resorted to trying to condescend me.

You wrote:

  > there is a difference between two APIs 
  > that both still work and having one
  > stable API.

As I explained, "this is the direct effect of high levels of backwards compatability. You can't change APIs; you have to create new APIs and then deprecate previous APIs."

I thought my point was obvious, but will explain it with more words:

If never making breaking changes to APIs is a strict requirement, all API changes must be additive. That means backwards compatibility entails the existence of more than one API to do the same thing. It seemed like you were insisting that there should be "one stable API" that never needs changes instead of "two APIs that both still work" and this is unrealistic for something that has existed and responded to changes in use for ~25 years.

  > if it has any kind of external 
  > dependencies or it relies on anything
  > that could change about the language, 
  > platform or other parts of your own 
  > code, then there is always a risk that
  > it will later break

This is a useful point. For dependencies that never make breaking changes you will be OK. But if the dependencies you have are likely to change and likely to be upgraded elsewhere in the codebase and potentially might make breaking changes, we should consider them a risk to the project.

I agree that this should be highlighted -- but, in the context of what you were talking about, which was with regards to code that uses old features of React, you are incorrect. As I mentioned to you, compatibility packages exist for all old React lifecycle methods and deprecated patterns. Therefore, by design, you are not being forced to upgrade the patterns in old parts of your codebase.

I am trying to make specific claims about concrete things that I can evidence. The existence of compatability packages for features that have been deprecated for 5 years invalidates a specific argument about needing to upgrade old React code due to changes in the API.

  > You've made several claims like that, 
  > but in the absence of data there's no 
  > way to know whether you're correct. 
  > For example, preset-env has been in 
  > production for 3+ years now and had
  > an extended beta/RC phase before that.
  > It's true that it defaults to ES5 if 
  > you don't configure it, but the Babel 
  > docs explicitly recommend that you do.
  > [..]
  > But it will take more than an unsupported
  > assertion to convince me that this has
  > been the norm for most web development 
  > for quite some time.

If it defaults to ES5 why are you asking for me to provide evidence as to whether companies have generally targetted IE11? It is the default; it is very unlikely that there is a majority of people that are configuring it...

  > But it will take more than an unsupported
  > assertion to convince me that this has 
  > been the norm for most web development 
  > for quite some time.

My claims are the following:

1. ES5 has been the default for front-end packages published to NPM since it was released (https://twitter.com/_developit/status/1289317757146693632). (I'm linking to Jason Miller's tweets since he has been the one most obssessively pushing for this to change. The problem we've all been having is that the `package.json` fields do not make it explicit what syntax a package is using.)

2. IE11 is in rapid decline (https://twitter.com/TheRealNooshu/status/1348955568459968515) and only recently have big corporations dropped support for it (Atlassian (March 2020): https://blog.developer.atlassian.com/retiring-ie11-support-f... ; Microsoft 365 (August 2021): https://docs.microsoft.com/en-us/lifecycle/announcements/m36... ; LinkedIn, Twitter, etc (2020): https://twitter.com/swyx/status/1260627626739130369). As I said "most only dropped IE11 this year". I guess I was off by one year, but I was talking about recent announcements.

For context, this was to evidence my opinion that the JavaScript community has been very slow moving and careful to output code that is executable by old browsers to the extent that we've supported a browser released in 2013 and used a syntax released in 2009.

  > And these kinds of things are advanced
  > tooling, in your view?

Check back to my text and you will see that I made no such claim.

You claimed that "the language doesn't provide much to help with building large-scale software and maintaining it over the long term" so I demonstrated that we have all of the necessary tooling to do so and invalidated this.

  > We had those in our IDEs for building 
  > desktop software back in the last 
  > century. Except they were automating
  > rewriting millions of lines of code [...]

Can you point me towards examples of the usage of AST rewriting tools that are actively being used by open-source library maintainers in other ecosystems to help their consumers do upgrades in large code-bases (e.g. I can see that `clang` has AST tooling, but I don't see examples online of this being widely used: https://devblogs.microsoft.com/cppblog/exploring-clang-tooli...).

Within the JavaScript ecosystem this is quite popular (1. https://github.com/reactjs/react-codemod ; 2. https://github.com/mui-org/material-ui/tree/HEAD/packages/ma... ; 3. https://github.com/emotion-js/emotion/tree/main/packages/esl... ; etc.) Teams that maintain huge codebases have tooling to safely automate their upgrades and the best library maintainers provide their consumers with these AST transformations.

  > Don't tell that to anyone who uses 
  > React Router. Or who builds their app
  > with Webpack. Or Babel, as you mentioned.

I agree that those particular libraries haven't been maintained well (they make extraordinarily large changes in major versions to the extent that sometimes it might as well be a whole new library).

  > I encourage you to look at what is considered the norm
  > and acceptable practice in fields where better quality 
  > and greater longevity are more highly valued. If we 
  > built security libraries or the embedded software 
  > controlling industrial machinery the way a lot of 
  > online companies build their web apps, we'd be lucky
  > to survive the night. 

I think your argument has been a moving target. Originally, you pointed your finger at React saying it has a stability problem, so we showed you that they've been incredibly good at keeping backwards compatibility and that you could upgrade your version of React to regain access to the ecosystem's newest libraries built on top of new APIs without needing to rewrite your legacy code through the usage of compatability packages.

Then you implied that it was an overall JavaScript ecosystem stability problem, so I showed you the level of effort that TC39 and the brower maintainers go to keep backwards compatability. And I showed you that most in our ecosystem have been carefully supporting the lowest commmon demominator users for almost a decade by producing web apps that work in IE 11 and packages that first-class ES5 syntax, and gave you examples of big webapps that only recently broke from this tradition.

Now you are pointing at exceptional cases involving particular poorly maintained libraries and tools, and telling me that we lack tooling to deal with scale (which is a separate concern). If you don't think Webpack and React Router are good citizens with regard to their API stability and this annoys you because you like to be on the latest/greatest then don't use them. I and many others also specifically avoid these libraries/tools and yet don't paint the whole ecosystem with this one brush. (On the topic of tooling, it has only been very recently that we've been getting tooling that can deal with high-scale development, however it is happening now.)

  *  *  * 

I think that possibly what you're noticing is the second-order effect of more and more usages of JavaScript and web technologies causing new APIs to steadily be added to the web with the old APIs remaining forevermore. The original APIs were made to display and navigate documents. As the years have passed more and more APIs have been released to support more complex types of applications and this resulted in overall churn in user-space as library creators iterate to produce better domain-specific APIs. We provide a high-level of user-facing stability despite this.

I don't think it is fair to compare what we are trying to achieve to what is important when controlling industrial machinery. The use cases of that are much more static, while in 2021 people on the Web are creating tools like Figma (https://www.figma.com/), Office 365 (https://www.office.com/), Buerli (https://buerli.io/), and Spline (https://spline.design/). This is very far diverged from where we started and the fact it has been achieved without breaking the web is impressive. It's also quite clear to me that high-quality tools like these aren't achievable without the creation of impressive and scalable tooling (some of which has been released to the public).

OK, let's agree to disagree...

[Silhouette]

I'm sorry if anything I wrote came across as condescending; that was not the intent. You seem reasonable enough, and objectively I agree with much of what you've said. However, I think we've been talking slightly at cross-purposes.

I won't try to go point by point now as these comments have become very long, but overall the difference between our positions (as I intend mine and as I currently understand yours) seems to be that you're focussing on specific technologies like JavaScript or React, while I'm talking more holistically about the entire ecosystem around them.

For example, you have talked about backward compatibility being excellent within JS-the-language, and about React continuing to support its class-based API alongside the functions-and-hooks alternative. That compatibility is not in dispute.

However, when I'm talking about stability, I'm also including everything that is built around JS or around React, the libraries and tools and documentation and people. And in these respects, the JS ecosystem is much faster moving and more fragile than almost any other language I have ever used.

The kind of bifurcation of APIs we've seen with React causes a lot of churn even if the library itself is still backward compatible. If you looked at blog posts or Stack Overflow answers or Reddit discussions about React from as little as three years ago, many of them would have little relevance to the newer API that has obviously become dominant within the community since then. On the other hand, if you hired someone with a couple of years of React experience today and asked them to maintain older code in your system that used the class-based API, they might have no idea what they were looking at. And if you found a useful library to work with React components but it only provides a hook-based API, again you can't use that functionality from your older class-based components. Your old code might still build, but it's essentially unmaintainable unless developers who have come to React more recently first learn what is effectively an entirely different library from their perspective, and even then you're limited in how much you can integrate that older code with more recent contributions to the ecosystem. (This paragraph is an elaboration on the point I was trying to make when I first joined this discussion.)

For the wider JS ecosystem, we've talked about the breaking changes in major tools like Babel and Webpack and in popular libraries like React Router. You suggest that these are "exceptional cases involving particularly poorly maintained libraries and tools". I suggest that there is, unfortunately, nothing exceptional about this sort of abandonment of earlier versions and interfaces within JS world. For one thing, Babel and Webpack aren't just any tools, they are arguably the two biggest names in the JS ecosystem, so when they break, the damage is widespread. For another, they are far from isolated cases. To give another example, Angular was React's big contemporary "competition" and it too essentially abandoned one API in favour of a radical rewrite for version 2, turning any project using the older framework into legacy code almost overnight.

Before React and Angular, we had a string of moderately popular UI libraries built around various levels of data binding. These were must-know technologies in their day for anyone who wanted to work on a project using them, but none remained popular for more than a few years, again leaving all of the individual knowledge and documentation and old code bases largely obsolete.

This pattern isn't unique to UI libraries, either. For example, as JS has evolved and added support for promises and then async/await, many older libraries whose interfaces weren't designed to support that programming style have been left behind, again including some that were very well-known and widely-used.

And with tools, it's a similar picture. Although Webpack is probably the most popular tool for building web app front ends today, over the years we've used shell scripts, self-contained tools like Browserify and Babel, task runners like Gulp and Grunt (with their own surrounding package ecosystems) to co-ordinate the ever-increasing number of tools used in build processes, more comprehensive tools like Webpack (again with a big surrounding package ecosystem) to try to unify everything in one place and bring some structure back, attempts to simplify the horrendous complexity that unification had introduced (the later versions of Webpack and the likes of Parcel), and now we're swinging back towards more specialised tools but in some cases with much better performance such as esbuild, but ironically these newer and better tools may be hard for a lot of projects to adopt because so many people are boxed in by their existing tools and have to wait for someone to provide some plug-in package for those existing tools in order to integrate the new ones. And again, breakage is not unique to Webpack. For example, not long ago, Parcel pushed out a breaking change, and because the effort from the Parcel devs is mostly focussed on the still-in-beta Parcel 2 that naturally has some major limitations of its own, this left teams using Parcel with broken builds either way until they figured out what the problem was and then probably rolled back to an earlier version of Parcel 1.

So I suppose my point is that all of that disruption can and does still happen frequently within the JS ecosystem, despite the backward compatibility of JS itself and the willingness of at least some of the big libraries to continue supporting old APIs after launching new ones. Stability, in the sense I'm using the term, implies a reasonable degree of backward and forward compatibility. The converse, unfortunately, does not hold. A good compatibility story is necessary but far from sufficient for a stable, productive ecosystem.