I'd say because JavaScript is insufficiently expressive. No macros, no arrow (pipe) operator, and the premier way of writing it is 4x as verbose than what I'd consider reasonable. D3 is a great library though.

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DanielHB 5 days ago | parent | next [-]

what do you mean by "arrow operator"?

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amiga386 5 days ago | parent | next [-]

Probably a reference to Clojure's arrow operator:

https://blog.frankel.ch/learning-clojure/2/

Something like a(b(c(d(e(7)))))) in Javascript could be written (-> 7 e d c b a) in Clojure?

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balamatom 5 days ago | parent [-]

Bingo.

	▲	5 days ago \| parent [-]
		[deleted]

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lionkor 5 days ago | parent | prev [-]

Maybe overloadable operators like in C++, where -> usually demotes some kind of deeper access into the object or abstraction? Or, the opposite, and abstracted access.

	▲	DanielHB 5 days ago \| parent [-]
		That is what I thought, but that doesn't make sense for a language without pointers According to the other comment it seems he meant the \|> pipe operator that is under proposal in js

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TheHeasman 5 days ago | parent | prev [-]

Uh, there are arrow operators in JS. D3.JS in Action Third Edition exclusively uses arrow operators.

(Trust me. I don't know jack about JavaScript, I had to get through the MDN docs to understand what they were, and once I did, made a whole lot more sense).

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tomku 5 days ago | parent | next [-]

The feature the person you're replying to is talking about is not arrow functions (`=>`), but what are called "threading macros" in other languages. In Clojure[1], the main one is named `->` and used as a way to thread a value through a series of functions that take it as a first argument, using the return value from the first function as the first argument to the second, and so on. It allows you to compose a series of plain functions to transform a value instead of (stateful) method chaining or nesting functions.

JS does not have a straightforward equivalent. The old and deprecated `with` keyword might seem similar but it's only a surface resemblance as it does not perform the return-value threading that makes the above pattern useful, it was meant for methods that mutate object state. There's a TC39 proposal[2] to add a pipe operator that would accomplish a similar thing to threading macros via an infix operator but it's still a draft.

[1]: https://clojure.org/guides/threading_macros

[2]: https://github.com/tc39/proposal-pipeline-operator

	▲	TheHeasman 5 days ago \| parent [-]
		I stand corrected. Thanks for pointing that out. Learned something new.

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balamatom 5 days ago | parent | prev [-]

And I know more about JavaScript than I'd like to, so don't trust me.