If I write
let x="hello"
let y="hello"
does Javascript make two references to the same string, or does it create two separate strings that happen to have the same content?
This first occurred to me when thinking about a micro-optimization. I had about 40 occurrences of an identical, 12 character string and I was wondering if that would take 12 bytes (plus whatever overhead) or 480. I quickly realized that was trivial either way so even if I modified the code to guarantee it’s the same chunk of memory, so what? But one could imagine cases where there could me a million copies of a 1000-character string, so it’s one of those things that would just be good to know.
It also led me to the broader question: How could I find out? In some languages I could dump the value of the reference and see if the two are the same, but I don’t know any way to do that in Javascript. And of course if I write “if (x==y)”, that’s going to be true because the contents are the same, so it would prove nothing.