That's precisely my issue with React though - JSX is a DSL that looks almost like normal HTML, but differs in small uncanny-valley ways. Sure, it's fine once you're used to it. But it's very much not standard HTML.
Just one example: the class attribute in HTML vs className in JSX.
It’s not that it’s complicated, you just use one or the other. But it’s very indicative of what’s going on under the hood: despite looking exactly like HTML, JSX isn’t creating HTML. It’s creating elements via JavaScript APIs.
The only "debatable" thing that React does is to use the names from the JS API in JSX (where some people would expect names from the HTML API because JSX looks like HTML)
That’s basically what I said, though? The point is that JSX is made to look like HTML so you think you’re writing HTML but you’re not, you’re using a JS API.
Also I had to laugh at the sibling replies:
> Narrative violation: className and friends are NOT a React thing!
> FWIW, the className prop is a React thing not a JSX thing
FWIW, the className prop is a React thing not a JSX thing. Other libraries which use JSX will happily accept a plain class prop. The React limitation is abstraction leakage: props are not attributes, they map to DOM properties.
But to the point that JSX is a DSL, that limitation is specifically because React itself is very tightly coupled to DOM semantics… but JSX explicitly has no built in semantics[1].
1: First sentence of https://facebook.github.io/jsx/ - “JSX is an XML-like syntax extension to ECMAScript without any defined semantics.”
That is just wrong on many levels. JSX brings an XML-like notation to JS. It has nothing to do with HTML. react-dom couples your React DOM to the real DOM - thus allowing you to use special JSX elements that create DOM elements. But then you / React interacts with them using the DOM API - not HTML source code.
Things like `htmlFor` or `className` should not be confusing - these are the official DOM properties. `style` in its DOM API also has an object-oriented API and not a string. If you are confused by these things (className vs class, ...) then potentially you started learning JSX from a completely misleading / wrong point.
I know most articles on React / JSX get that wrong, but this non-sense has to stop. After all, you do not write React in the browser because you want to generate HTML - you do write it to manipulate the DOM. On the server, you may want to generate HTML and then this can be misleading (true), but this has not been the main objective.
Telling someone they learned something wrong maybe isn't the best approach when trying to explain why something should not be confusing. Especially when it's a widely held view, maybe the learners are not the problem.
Most people learn JSX when they learn React. It was created by Facebook for React, after all. What does the React docs teach about className?
Here in the intro it doesn't even explain that you need to use className instead of class. It uses it with no explanation. Then it throws in a line about camelCasing and assumes that you understand why it changed.
Finally! In a page that seemingly has nothing to do with JSX we get told to change how we write HTML, but we're not even told why. (The htmlFor section tells us.) No wonder people are confused.
Yes, className is a property of the Element interface but it is not the attribute used when writing HTML. You're still changing how you write HTML. It is no longer standard. That is the point people are making here - JSX introduces enough edge cases that you must learn that it adds equally as much mental overhead as the template DSL for Alpine or Vue. Even if people understand the reasoning and it is not confusing, it's still a shift.
> Here in the intro it doesn't even explain that you need to use className instead of class.
Again, because `className` is not React specific, it's JS DOM API specific. Sounds like the real problem is that people start learning React without fully learning the JS DOM API itself, then they get confused when things like `className` or `htmlFor` show up.
> Yes, className is a property of the Element interface but it is not the attribute used when writing HTML. You're still changing how you write HTML.
You're not writing HTML. That's the entire gist of the parent comment. It looks like HTML only insofar as HTML is a type of XML. But what you're really doing underneath is something like:
JSX is simply syntactic sugar on top of DOM operations like that (albeit within the context of a renderer like React; Svelte eschews a renderer entirely and truly is creating DOM operations like above). In React, JSX would be direct syntactic sugar for:
It is standard, it is in the Element API, I don't know how it can get more standard than that. Again, it sounds like the problem is that people really should learn JS and DOM separately before ever touching React. Sadly, too many beginners in web dev and programming in general gravitate towards a React/Node stack, which are good production tools, but they really ought to know how we got there.
Now why I don't use DSLs is because they don't use the standard of the JS DOM API, they use their entirely new creation, like v-for or #if :else. That is why I consider Vue or Svelte templates to be DSLs while not JSX, because the latter is fully compliant with the Element spec, and it uses plain JS/TS, unless you define a DSL to be so broad as to be literally any transformation of code, which, well, I can't practically agree with.
> JSX is a DSL that looks almost like normal HTML, but differs in small uncanny-valley ways.
My point was not that its a common misconception that JSX has something to do with HTML - therefore comparing it to HTML and then being surprised that it isn't, shouldn't come as a surprise.
Also it does not differ in small uncanny-valley ways. Just one example on the syntax level: HTML has real self-closing elements (e.g., `<img>`) while JSX requires you to explicitly self-close (e.g., `<img />`). In HTML you also cannot explicitly self-close any element (e.g., `<div />` will just be parsed like `<div>`), while in JSX you can. I don't even want to start about whitespace etc. - those things are actually found / listed in any decent JSX tutorial.
I strongly agree but looking at the Alpine examples it feels like the worst of both worlds to me. At least JSX allows code checking etc, putting code inside HTML attributes has a real ick factor for me.
No, you're not. There is no JSX of any sort in the example the parent commentor provided, nor in the approach that they present, even outside of that specific example.
The first parameter is the component, which is string containing the HTML tag name for built-in components which are basically just HTML elements, such as div, span, img, h1, etc, but the actual component (a function or a class) for any other type of component. The second parameter is the props. The third parameter is the children, which happens to be a string in this case because the content of the h1 in the example is pure text, but if you'd want anything more complicated as children, you couldn't put in a string and pass that, you'd provide it more React.createElement -provided values.
React at it's core is a function (or set of functions) that interpret strings like "h1" into DOM elements in a browser.
JSX is a shorthand for writing those function calls. <h1> becomes React.createElement("h1"). Sure you are still largely using HTML element names, but that's only because people don't really use JSX for anything else. The whole point is that it's easier to write JSX than the underlying function calls.
