How does the minus minus less than "-->" operator work in JavaScript?

Question

while (max --> min)
{
    console.log(n);
}

I know that --> decreases the value, but where is --> documented in the official documentation?

it's two things ... post decrement `--` and a greater than comparison `>` — Jaromanda X, Aug 26 '16 at 10:00
`-->` is `--` followed by `>`, two operators... So `max-- > min` if you prefer. — Jean-Baptiste Yunès, Aug 26 '16 at 10:01
Somebody either slipped on the keyboard or they thought they were being clever… — deceze, Aug 26 '16 at 10:03
@deceze I'd never seen that before, I think it is kinda clever :)! It's like a pun, but with code. — James, Aug 26 '16 at 10:05
@judgeja Any cleverness that spawns a question on SO because the reader goes *"WTF?!"* is bad cleverness… — deceze, Aug 26 '16 at 10:07
see also [this highly upvoted question](https://stackoverflow.com/questions/1642028/what-is-the-name-of-the-operator-in-c) (currently the 8th highest upvoted question overall) — Mikescher, Aug 26 '16 at 10:54
Could someone please explain to me why a single line of JavaScript code starting with '-->' simply does nothing? — simonmysun, Jul 06 '18 at 08:20

score 26 · Accepted Answer · edited Aug 26 '16 at 10:01

26

It is the post decrement operator -- followed by the greater than operator >. Just the spacing is weird.

while (max-- > min)

So, while max decremented is larger than min…

edited Aug 26 '16 at 10:01

zerkms

answered Aug 26 '16 at 10:00

deceze

3

Just a nitpick, wouldn't "`max` decremented is larger than `min`" be better suited for something like `--max > min`? – Aioros Aug 26 '16 at 11:55
1

@Aioros *"`max`'s value which is decremented afterwards is larger than `min`"* seemed a bit unwieldy. I expect everyone knows how `--` works… :) – deceze Aug 26 '16 at 11:56
would this work in for loop like `for( let i = 0; i++ < n; )` – Rahul Yadav Apr 13 '21 at 23:10
Check out this CodeWars kata: https://www.codewars.com/kata/6359bf1600fba287b6189f9b/javascript Apparently, "-->" on its own is a valid piece of JS code. – Maksym Shcherban Nov 12 '22 at 21:51
P. S. After 5 more minutes of Googling, I now know that due to historical reasons, HTML comments are valid JS code :D – Maksym Shcherban Nov 12 '22 at 21:56

1 Answers1