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Comment by hunterb123 | Hacker News Reader

Repeating a blog post over and over doesn't make it true.

The author is wrong. Most of his statements are about React, not JSX.

It's syntactical sugar for nested function calls, that's all. Brackets are turned into function statements, attributes are turned into object props.

The author conflates React properties with JSX, which is wrong. The author also confused JSX limitations, you cannot do statements because it's a single expression.

Please go read the JSX spec instead of some random blog post.

https://github.com/facebook/jsx

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Thank you for that definitive link. Note that first boldfaced sentence in that JSX specification is as follows: "It's NOT a proposal to incorporate JSX into the ECMAScript spec itself."

That should have been the end of this discussion and fight that you picked about your incorrect statement that "JSX is JavaScript". You just unwittingly undermined and terminated your own argument by linking to the JSX spec itself, which clearly and explicitly says you are wrong, in BIG BOLD WORDS.

As JimDabel said, "They wanted to be 100% clear about it." So stop repeating something that the JSX designers so insistent is not true that they put it in bold at the top of their design specification.

You already won this argument, for the "JSX is NOT JavaScript" side. It's over.

You're arguing the wrong thing. You're arguing a semantics debate about whether an extension is JS. I'm arguing that it allows you to use JS features instead of a custom template system.

In the semantics debate you want to have I think it is JS because it all becomes JS bytecode and it's just nested function calls in the end, but that's subjective. If you want to be pedantic it's a JS extension, but in the future it could be JS if the spec is merged into engines not the compilers.

JS is an umbrella term, you're arguing it's not Ecmascript, okay, I never said that. I said it's JS, and you want to have a tussle about it instead of comparing templating systems.

Also you're very rude.

Right from the very top of your source:

> JSX is an XML-like syntax extension to ECMAScript without any defined semantics. It's NOT intended to be implemented by engines or browsers. It's NOT a proposal to incorporate JSX into the ECMAScript spec itself. It's intended to be used by various preprocessors (transpilers) to transform these tokens into standard ECMAScript.

Further down:

> Why not just use that instead of inventing a syntax that's not part of ECMAScript?

It is not JavaScript.

We're splitting hairs now. It's an extension of the JS spec. Once a parser adds this grammar it is JS.

It's syntactical sugar, unlike template syntax #if, ng-if, etc.

Your argument is it's not part of the current Ecmascript spec, I never said it was, but if a parser or engine adds these two new PrimaryExpressions and attributes, it is JS.

The entire point is JSX extends JS to allow templating via nested JS functions w/ pretty brackets instead of creating an entire templating system.

Under your reasoning nothing that isn't in the current accepted Ecmascript spec implemented by browsers is JS. Does that mean decorators aren't JS? Were async functions not JS before they were in browsers?

We’re not splitting hairs. It is, quite literally, not JavaScript in a fundamental way.

If you want to go around telling people it’s a non-standard extension to JavaScript or if you want to go around telling people it’s a superset of JavaScript, then by all means do that. But it is simply not JavaScript. Why do you insist on saying otherwise? All that does is start completely pointless arguments. What do you gain from insisting it is JavaScript when it isn’t?

I think you're getting a little too worked up.

The point is this small extension to JS grammar lets you do templating with normal JS, instead of #for you can use .forEach, .map and other array methods.

You can use JS instead of replacing tokens in a template.

It's not a superset of JS, that's not accurate, it's an extension of the spec.

I hope the JSX spec is added to the standard sometime to stop this stupid debate.

Until you realize what JSX is you don't realize the full potential it has over templates.

> The point is this small extension to JS grammar lets you…

If that’s the point, why are you telling people it’s JavaScript? You can make that point just fine without starting arguments.

Saying “This is an extension to JavaScript” is fine. Saying “This is JavaScript” starts arguments. What is your goal here?

> I hope the JSX spec is added to the standard sometime to stop this stupid debate.

But you are starting this stupid debate by telling people it’s JavaScript when it isn’t. If you are tired of people pointing this out when you call it JavaScript, why do you do it? There seems to be absolutely nothing to gain from that except “a stupid debate”.

> Until you realize what JSX is

I know what JSX is. I’ve written plenty of JSX.

> you don't realize the full potential it has over templates.

We are not talking about the value of JSX, merely whether it is JavaScript or not. JSX could cure cancer, but it still wouldn’t be JavaScript.

> If that’s the point, why are you telling people it’s JavaScript? You can make that point just fine without starting arguments.

First, I say it's JS because it is. Just as decorators are JS. By being an extension of JS it is JS. The two are mutually inclusive.

Second, I didn't want to start an argument, I wanted to call out the very wrong blog post, how it referenced React not JSX, how the spec is an extension of JS, explain the limitations, etc. Until now it was more of a debate. Now it's a bit more of a semantics debate unfortunately.

> But you are starting this stupid debate by telling people it’s JavaScript when it isn’t. If you are tired of people pointing this out when you call it JavaScript, why do you do it? There seems to be absolutely nothing to gain from that except “a stupid debate”.

Actually if you go up the comment chain you'll see I didn't start this debate. If you're tired, just don't participate.

> We are not talking about the value of JSX, merely whether it is JavaScript or not. JSX could cure cancer, but it still wouldn’t be JavaScript.

Oh but we are, again if you go up the comment chain, it's being compared to Svelte's template system, that's how it got brought up, and that's usually why this topic gets brought up. You don't have to create a whole template system. You just use nested functions. To use pretty brackets it needs a small extension of the spec. You don't have to come up with a loop system, a conditional system, etc.

> By being an extension of JS it is JS. The two are mutually inclusive.

This is absurd. If JSX were JavaScript, JavaScript wouldn’t need to be extended to include JSX. The whole point of it being an extension is that JavaScript doesn’t include it, therefore JSX extends it. If JSX were JavaScript, then JavaScript wouldn’t need to be extended. The two are mutually exclusive.

> > We are not talking about the value of JSX, merely whether it is JavaScript or not. JSX could cure cancer, but it still wouldn’t be JavaScript.

> Oh but we are, again if you go up the comment chain

In the context of “Is JSX JavaScript?”, the value of JSX is irrelevant. Whether JSX is useless, useful, or amazing makes zero difference to the question of whether JSX is JavaScript or not.

You can still go around telling people JSX is great. It doesn’t have to be JavaScript for you to do that. People telling you that it isn’t JavaScript aren’t telling you that it’s worthless. They are just telling you that it isn’t JavaScript.

Are decorators JS? Answer that question and I'll respond to the rest of your comment.

We're talking in circles a bit so I'd like to drill that down first.

Decorators are a stage two proposal. This means that they are not yet JavaScript, but are expected to be soon.

The point of all of this is it's a JS feature, not a system written on top of JS. A few syntax changes unlocks the rest of JS instead of having to reinvent the wheel, making your own loop and conditional systems. I don't see why the semantics of it not being included yet doesn't make it JS.

When the feature isn't in all browsers and only Babel doesn't make it not JS, similar to how async functions were JS before being natively in JS engines.

You're not being genuine when you say decorators aren't JS. No one looks at Angular 2 and says "whoa that's using some foreign language mixed with JS", they say it's using a JS experimental feature.

I'll concede that it's not "JS" it's an "experimental JS feature", I'll use that in the future to avoid this pedantic debate.

> I don't see why the semantics of it not being included yet doesn't make it JS.

You don’t see why something not being included in JavaScript doesn’t make it JavaScript? Really?

> I'll concede that it's not "JS" it's an "experimental JS feature"

JSX is not an experimental JS feature. You’re trying to draw an equivalence between decorators and JSX, but they aren’t equivalent at all.

Decorators were submitted for inclusion into JavaScript. They have undergone a lot of review to determine whether they belong in JavaScript, and people agreed they did. The specification has been refined to make them suitable for inclusion into JavaScript. Everybody plans on decorators becoming part of JavaScript. Browsers will implement decorators.

JSX, on the other hand, is explicitly not proposed for inclusion into JavaScript. The second and third sentences of the JSX specification read:

> It's NOT intended to be implemented by engines or browsers. It's NOT a proposal to incorporate JSX into the ECMAScript spec itself.

The second sentence is even bolded in the specification. They wanted to be 100% clear about it.

The standards committee isn’t reviewing JSX for suitability for inclusion into JavaScript. Nobody is planning on JSX becoming part of JavaScript. No browsers are planning on implementing JSX.

These are two entirely different situations. Decorators being on the cusp of becoming JavaScript does not mean that JSX is JavaScript.

So far he's ignored instead of addressing all the valid points you've made, and now he's trying to derail the conversation by bringing up experimental features, which, as you say, have nothing to do with anything else.

Since he's working from his own definition of the word "is", and his own definition of the JavaScript standard, there's no way he's going to admit what he said is wrong, even though it is, and the JSX designers were 100% clear in their documentation about shooting down his mistaken idea that JSX is JavaScript.

Now that you've made that point, he's probably just going to try to derail and change the subject again, like he was just trying to do by diverting the discussion to decorators.

https://news.ycombinator.com/item?id=29195015#29208291

> The point is this small extension to JS grammar lets you do templating with normal JS, instead of #for you can use .forEach, .map and other array methods.

But then React is much more than just "small extension".

Hooks alone are less of a Javascript than any Svelte template syntax.

We're not talking about React we're talking about JSX.

Svelte has a lot more going on than it's template language as well.

We're only comparing the templating system to JSX.

Let's compare to JSX then: https://news.ycombinator.com/item?id=29194287

That's still React. JSX is only turning brackets, tag names, and attributes into function calls and object properties.

Special attributes, events, etc. are React specific and not related to JSX.

Basically it's a clean way to represent nested function calls, that's it. It has nothing to do with React nor does it need React.

<tag prop="value"/> gets turned into React.createElement('tag', {prop: "value"})

That's all. Period. The special props React introduces has nothing to do with JSX.

Also you can customize JSX to change the functions it generates. (i.e. swapping out React.createElement)

https://news.ycombinator.com/item?id=29206956

Those are all features of React or the React JSX transform, not JSX. Other JSX transforms or frameworks using them may or may not share any or all of them. (JSX is not only used in React.)

Ah. So we're comparing a specific templating language (Svelte) with an idealized and nonexistent version of JSX (JSX is a non-standard extension that has different flavors depending on what underlying framework, and versions of a framework, you use).

and if you really want to use statements, you can, using an IIFE for example. It’s not pretty but you can because… ehm… it‘s just javascript.

At this point the "is JSX just javascript" discussion has gone on a little to long imho. It feels like "is html a programming language". We all have strong convictions about the answer but it doesn‘t matter, really.

It‘s interesting that fans all of 3 frameworks constantly claim that it’s "just“ or "closer to vanilla" html or js. Should we really care anymore?

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