What is the meaning of double at sign (@@) before a symbol name

Question

In the context of ES6 symbols, it's often seen that double at sign (@@) is placed before a symbol name. Is it just another way to reference a built-in symbol? However, using it in code causes

SyntaxError: Invalid or unexpected token

can you show an example of where you saw this? – Ibu Jul 24 '17 at 23:18 — Ibu, Jul 24 '17 at 23:18

score 5 · Accepted Answer · answered Jul 24 '17 at 23:19

5

This has been answered before: What does @@ ("at at") mean in ES6 JavaScript?

I am gonna leave this article here too: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Iteration_protocols

A summary quote from the spec:

Well-known symbols are built-in Symbol values that are explicitly referenced by algorithms of this specification. They are typically used as the keys of properties whose values serve as extension points of a specification algorithm. Unless otherwise specified, well-known symbols values are shared by all Code Realms (8.2).

I hope this answers your question :)

answered Jul 24 '17 at 23:19

Max

1,526
2
16
19

If a question is a clear duplicate, best to flag it as a duplicate and leave it at that. https://meta.stackexchange.com/a/10844/220438 – loganfsmyth Jul 24 '17 at 23:39
riiiight, actually didn't know, thanks – Max Jul 24 '17 at 23:51
1

I found this answer quite helpful, especially the Mozilla docs link – pjdavis Feb 28 '19 at 19:25
I still don't understand what is well know symbol. It is so badly named. – Nicolas S.Xu Oct 24 '22 at 18:16

What is the meaning of double at sign (@@) before a symbol name

1 Answers1