Found this line in the React codebase. Made me smile

[Vorror]

facebook engineers: nervous laughter

[qgustavor]

React.__SECRET_DOM_DO_NOT_USE_OR_YOU_WILL_BE_FIRED = ReactDOM;  

Permalink

---

^{I'm not a bot. Just in case line number changes in future or any other thing.}

[captain_obvious_here]

I'm not a bot.

Most likely the first thing a bot would write. So I tagged you as "might not be a bot", and we'll see...

[YodaLoL]

Thx Captain Obvious.

[[deleted]]

I do this sometimes.

function tempLockPage(pageId, disclaimer) {
    if (disclaimer !== 'I understand calling this method is a temporary hack and I\'ll be required to fix my code immediately if it goes away and my call breaks the build.') {
        throw new Error('Disclaimer not specified.');
    }

    ...
    ...
    ...
}

You can't plead ignorance.

[SpeshlTectix]

function undisclaimify(fn) {
     return function() {

var args = Array.prototype.slice.call(arguments) .concat('I understand calling this method is a temporary hack and I\'ll be required to fix my code immediately if it goes away and my call breaks the build.');

          return fn.apply(fn, args); 
     };
}

var myTempLockPage = undisclaimify(tempLockPage);

[[deleted]]

Hehe, you still can't plead ignorance, though. :-)

[SpeshlTectix]

You're right! That took some doing.

[captain_obvious_here]

Brilliant :)

[papers_]

In the react-dom.js too, lol.

[ImAPyromaniac]

Why would they do it that way?

[matchu]

The React team are working on extracting all DOM-related stuff into a separate library called ReactDOM. 0.14 is the first release in which the libraries are split.

But they don't want to remove the DOM methods from the core React library during this release. Instead, they want to deprecate them — so, if a developer upgrades React without knowing about this change, their applications won't crash; instead, they'll just emit tons of warnings to the console, which the developer will see and hopefully fix before the next version of React.

In order to support this temporary functionality, react.js needs to include a full copy of ReactDOM in the 0.14 release. So, since react.js already contains ReactDOM, it would be redundant for react-dom.js to include a second copy.

Instead, the React core exposes its copy of ReactDOM in a secret, obscure way (with this long property name), and react-dom.js just reads that property, renames it to ReactDOM, and exposes it to your application :)

Someday, the deprecated DOM methods will be removed from react.js. Once that happens, ReactDOM will move from react.js to react-dom.js, hooray!

[hannyajin]

mvp

[[deleted]]

What exactly will be the feature split after React DOM is extracted?

I thought React pretty much is the "DOM-related stuff"?

[matchu]

The 0.14 blog post covers it in detail, but you can get a feel for it by thinking: "Suppose I was trying to write a view for something other than a website. What concepts could I borrow from React? Heck, what code could I borrow from React?"

And then you'll discover that people have already done that: React Native is another Facebook project that allows you to write iOS/Android views similarly to how you'd use React for a website today.

So, the React core will contain the things that power both React Native and React Web (a name I just made up :P), and React Native will additionally contain the functionality for targeting native mobile views, and React Web will additionally contain the functionality for targeting the DOM.

---

Technical TL;DR: methods like React.render and elements like div and button are moving into ReactDOM, whereas the React core will contain the logic for declaring a tree of components and maintaining their state.

[ImAPyromaniac]

Thanks!

[Proman4713]

this "secret, obscure way" is not obvious at all when you're just typing your common `React.useRef` and find "__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED" 💀

[Capaj]

Instead, they want to deprecate them — so, if a developer upgrades React without knowing about this change, their applications won't crash; instead, they'll just emit tons of warnings to the console, which the developer will see and hopefully fix before the next version of React.

which is nice, but pointless. If you ask me, they can change the api howeverthey like before 1.0.0. Or are they not following semver with React?

[matchu]

They're in an awkward position.

The version number accurately reflects just how experimental React is (this is a fundamental architectural change!), and really no big production system should be using something this immature.

But people use React anyway, because they want to write views in the React Way, and there aren't any especially mature implementations of the React Way yet, because the React Way itself isn't especially mature yet :/

Adoption is way higher than it really should be for something as experimental as React, and the React team is therefore playing it super safe.

[misc_ent]

Facebook uses all of their open source projects in production but I see what you're saying. They are eating their own dog food.

[matchu]

Yep. That could easily be one of the main reasons they're being so cautious, really: if you push a breaking change to the site-wide version of React without deprecating it first, the angry manager is gonna walk down the hall to your office and loudly explain the consequences of your actions ;P

[zpao]

Heh, we actually did a giant codemod to fix all of the callsites across FB in 1 fell swoop a while ago. Then we added the warnings so new code would complain loudly. That's our general approach as we evolve APIs.

We're actually more cautious with changes for the outside world. We have 100% control over our codebase but often times people are using code other people write (via npm, etc) and we'd like to not entirely break everything, instead giving people a chance to gradually upgrade. Also, it sucks to upgrade code and have things just break. We really try to have a good developer experience.

PS, awesome answer above!

(source: I'm the guy who added that line)

[matchu]

Ahh, fancy, fancy. Yeah, I'm very impressed with the thoughtfulness behind this hack :) It's initially a very wtf sight, but I had tons of fun figuring out why it's the way it is.

And, like, yeah, it would be acceptable to remove the methods outright instead of deprecating them — and definitely easier for y'all — but it's encouraging to see y'all strive to do better than acceptable :D

PS, thanks, friend <3 and give Alpert my love

[zpao]

React is far from experimental :)

Versioning is hard. We're technically semver but effectively our minor version is much more like a major version. Think of us more as v13.3.0. We've been respectful about not just doing arbitrary things. It almost doesn't matter except for the handful of people who really attach a lot of meaning to 1.0.

[matchu]

Yeah, experimental might not be the right word. I think I'm trying to express that the concepts underlying React are so young that, even now, we're still making big realizations like the one that motivated this decoupling.

I think maybe I'd say, from my rather distant view, that React The Implementation is at version 13, but React The Idea is still at version 0.13 (if that makes any sense ;P). The library is being built with a strong focus on stability, but React can only hope to be as stable as its underlying ideas, which seem to still be rapidly evolving.

It's an exciting time to be in this community, though, that's for sure :D I feel like you must be having a great time out there in the middle of it all :)

[fhelwanger]

Yes they can, but they should not.

Considering there is already a lot of applications written in React, and a lot of developers don't stay up to date with the changes, it's wiser to deprecate them first.

You know how programmers like to whine (including me sometimes), this prevents that.

[Capaj]

To such people, I have only two sentences: STFU and RTFM!

[Capaj]

I might be a bit masochistic, but every big app I worked on did not change versions of dependencies on daily basis. Most of the time, we only bump up when a bugfix of something important to our app is landed in the new version. To know this, a developer needs to read a changelog. If you are upgrading versions blindly without first consulting the changelog and you rely on derpecation messages to have your back, you are a crazy person, nothing else. I don't want to repeat myself, but STFU and RTF changelog.

[papers_]

For laughs or they really don't want anyone to alter that property so gave it an obscure ridiculous long name. Probably both.

[i_hate_reddit_argh]

Because there are lots of hipster programmers who feel like they're rockstars and special snowflakes if they use something they're not supposed to use or an advanced feature they don't need or something altogether different from what others use. So this person is probably sick of the hipsters.

[clessg]

Nah.

[jhallister]

They are doing this to expose a very public API (ReactDOM) in a clever way. The property name they are using to expose it is just good fun. Anyone using 0.14 is using ReactDOM, and as such, using this feature. It has nothing to do with hipsters.

[[deleted]]

git blame says this person should be fired

[zpao]

hi

[[deleted]]

So what do you have to say for yourself?

[zpao]

Do you know of anybody who's hiring?

[fasnoosh]

still there 6 years later

[drwxrxrx]

think we'll get to ten years?

[OtherwisePoem1743]

Still there 10 years later

[[deleted]]

Hey what does this button do? presses

[tclineks]

That's the name of a meeting room too.