Comment by balamatom 3 days ago
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.
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?
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).
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.
I stand corrected. Thanks for pointing that out. Learned something new.
what do you mean by "arrow operator"?