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Comment by Zanfa | Hacker News Reader

> JSX really isn’t that great. Sometimes it feels like most React devs don’t know how to write a for loop or if statement because they mostly use map(), ternaries, and short-circuiting, which are not very ergonomic compared with markup-based approaches.

I'm the last person to vouch for React and the horrors it has inflicted upon web development, but the one thing it definitely got right compared to Angular (and Vue) is the use of JS for control flow, rather than fake attributes and whole new language.

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JSX is as much a new language as Vue’s templating. JSX extends JavaScript syntax; Vue extends HTML syntax.

If you’re working on generating markup, it makes more sense to do that at the markup level than constantly switch between markup and imperative JavaScript.

It might use JavaScript for control flow, but does it really count when it uses it in a way that is not idiomatic at all? It’s not idiomatic JavaScript to use map instead of for everywhere, and it’s not idiomatic JavaScript to use ternaries instead of if everywhere. Writing JSX looks very different to writing normal JavaScript.

The difference is that JSX is using control flow from an actual programming language, whereas Vue is shoehorning control flow into declarative markup. This is the single reason React won the frontend framework market: they got the templating right.

PS: in modern JavaScript, using map rather than for loops is more idiomatic!

> This is the single reason React won the frontend framework market

Don’t be silly, the front-end landscape is a lot richer than you make it out to be. React hasn’t “won”, the last time there was a clear winner in front-end, it was jQuery.

> PS: in modern JavaScript, using map rather than for loops is more idiomatic!

No, it’s not, and this is exactly what I was talking about. for loops and map() serve distinct purposes.

for iterates through a series of elements.

map() transforms a series of elements.

It’s possible to use them both for the same things, but there is a very clear semantic difference between them. One doesn’t replace the other, they mean different things.

In the context of “I have a bunch of elements I want to iterate over and output”, what you want is a for loop. The reason why React devs have been convinced map() replaces for loops is that React has to force you into making everything an expression, so instead of writing for when it’s appropriate and map() when it’s appropriate, they have to write map() everywhere.

It’s good you ended on the one thing JSX got right: everything is an expression. It’s that simple. There’s nothing imperative about evaluating a template, it’s entirely covered by functional programming techniques. You’re just producing a value.

And yes, modern JavaScript uses tons of concept from functional programming, where it is understood that mutating values and triggering side effects should be a last resort. This is why a good js programmer uses ten times more maps then he uses for loops.

Maybe you don’t know how dominant React is today? Two third of JavaScript developers use React at work (https://2024.stateofjs.com/en-US/libraries/front-end-framewo...).

It feels like you’re out of touch, have you used JavaScript lately?

> mutating values and triggering side effects should be a last resort.

Output is a side-effect.

> This is why a good js programmer uses ten times more maps then he uses for loops.

This is a) massively overstating things, and b) not relevant to a case where zero for loops can be used.

> Maybe you don’t know how dominant React is today? Two third of JavaScript developers use React at work

I checked those figures before I posted that comment to double-check my memory. Two thirds is not anywhere close to “React won the market”. Android has ~72% global market share, but I’m sure you wouldn’t say that Android has won the smartphone market.

> It feels like you’re out of touch, have you used JavaScript lately?

We disagree, that doesn’t mean I’m out of touch. Try not to be so insulting.

It’s not an insult, if you think for loops are commonplace in modern JavaScript and React isn’t the dominant frontend framework by far (twice more used than the next in line, vue), you’re out of touch, it’s just a statement.

How can you not realize that producing a string or a tree of elements is a purely functional operation? There’s no side effect here. Are you familiar with the concepts of functional programming?

You are being insulting because every time we disagree, you ignore half of what I am saying to assume I don’t know what I am talking about. Two informed people can disagree but you don’t seem to get that. A conversation is not a competition where one person gets to prove the other person is ignorant.

Take “React winning”. We disagree that React won because I don’t think 66% of a market is “won”. But you jumped to the conclusion that I just didn’t know what I was talking about. Then I clarified that the difference in our opinion is not the knowledge of the market share but our judgment of it, and I gave the example of Android not having “won” the smartphone market with ~72% of the market… and you just ignored that and doubled down on calling me out of touch.

Take the use of map(). I am very clearly distinguishing between common usage and defined semantics. The gap between the two was what I was complaining about. But you ignored what I was saying and decided that I don’t know map() is used a lot in modern JavaScript, when that was the core of my complaint!

And for functional programming techniques, we disagree in how we think about the operation. You see it as data processing, I see it as I/O. I very specifically pointed out that I/O is a side-effect. This is a mainstream viewpoint in functional programming. But you ignored what we actually disagree about and assumed it’s just because I don’t know anything about functional programming.

Your approach to disagreeing with me is to ignore half the things I say so that you can attack me for being clueless. You need to do better.

I still think you’re misunderstanding what React is optimizing for. When you say "React has to force you into making everything an expression", you’re describing its core philosophy, not a constraint. JSX is built around the idea that rendering is just data transformation. It's UI as a function of state. That’s why using map() is idiomatic here. You’re building trees, not iterating imperatively.

Also, it bears repeating that React isn’t just slightly dominant. 82% of JS developers have used it according to the 2024 State of JS survey, and for good reason. It shaped the modern frontend mindset in a way that Vue or Angular haven’t, despite their own merits. For instance, many frameworks came up with their own version of hooks. It's telling that most new frontend frameworks are aiming for the "better React" position.

I realize we just have different interpretations of what "winning" means in a fragmented ecosystem, but it’s worth acknowledging how much React has set the tone for modern web development. UI as a function of state (and using map() a lot...) is here to stay.

> And for functional programming techniques, we disagree in how we think about the operation. You see it as data processing, I see it as I/O. I very specifically pointed out that I/O is a side-effect. This is a mainstream viewpoint in functional programming. But you ignored what we actually disagree about and assumed it’s just because I don’t know anything about functional programming.

I think you're wrong here. The point at which the rendered template is actually stuffed into the DOM (and hence the screen) is I/O, sure. But the creating / rendering of the template is a pure function, which is what we are dealing with here.

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