Rick Waldron wrote:
On Wed, Oct 3, 2012 at 1:57 PM, Herby Vojčík <[email protected]
<mailto:[email protected]>> wrote:
Rick Waldron wrote:
On Wed, Oct 3, 2012 at 12:56 PM, Herby Vojčík <[email protected]
<mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>> wrote:
Nicholas C. Zakas wrote:
After a little more experimenting with sets (still a
really big
fan!!),
I've come across an interesting problem. Basically, I found
myself using
a set and then wanting to convert that into JSON for
storage.
JSON.stringify() run on a set returns "{}", because
it's an object
without any enumerable properties. I'm wondering if
that's the
correct
behavior because a set is really more like an array
than it is an
object, and perhaps it would be best to define a
toJSON() method for
sets such as:
Set.prototype.toJSON = function() {
return Array.from(this);
It depends... you should be able to reread it, so the best
thing
would proably be to use matching set of transformers for both
stringify and parse. I personally would rather see
something like
{ _Set_from_: Array.from(this) }
here.
};
The revived array can be passed as an arg to new Set(revived) :
new Set(JSON.parse(s.toJSON()))
I am talking about deep nested structure with (possibly) multiple
sets all over. Your solution is unusable, you need to explicitly
know where the arrayified sets are.
Fair enough, my solution definitely doesn't scale.
In that case, I'd say it's not the language's job to try and guess what
the user code wanted to do with a serious of deeply nested, stringified
arrays in a JSON string. Seems like a non-starter.
I am worried you are accusing me of something Bad (TM) I did not
actually proposed.
I said, ones cannot used .toJSON because you need to read it back, so
you should serialize / deserialize by some protocol, for which you need
to supply the transforming functions, JSON.parse as well as
JSON.stringify have extra parameters for them (plus contemplated the
idea that such composable wrappers/unwrappers for Sets, Maps etc. could
be supplied because they can be handy, but probably library is the
better level for this than the language).
Rick
Introducing another Set constructor just to wrap the above is
early-warning feature creep. toJSON is an intuitive addition
Definitely not "feature-creep another Set constructor".
Rick
Herby
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