Traversal in insertion order for Set.prototype.add/delete

Qantas 94 Heavy qantas94heavy at
Wed Apr 23 20:54:02 PDT 2014

> We need a deterministic order. What deterministic order do you suggest?
> Why would it be better?

Sorry for the confusion, I completely worded that wrong.

I'm specifically referring to the specification sections
and (specifying the behaviour for Set#add and Set#delete), which
states that:

6. Repeat for each e that is an element of entries, *in original insertion
> order*

I don't see any real reason why that's needed, unless there's some odd side
effects of doing so that I'm not aware of. Sets are meant to be unique and
I don't think the order of checking whether the element already exists
really matters. I'm not advocating for any change for the deterministic
order of iteration in Set#forEach and for-of loops on sets.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the es-discuss mailing list