JSON support for BigInt in Chrome/V8
Andrea Giammarchi
andrea.giammarchi at gmail.com
Tue Jul 17 09:49:01 UTC 2018
fair enough, so everything that is not `object` or `null` should never use
`new`. Is this somehow an indirect rule based on current specs or actually
part of the specification?
On Tue, Jul 17, 2018 at 11:12 AM J Decker <d3ck0r at gmail.com> wrote:
>
>
> On Tue, Jul 17, 2018 at 1:48 AM Andrea Giammarchi <
> andrea.giammarchi at gmail.com> wrote:
>
>> We miss a fundamental feature in JS, the ability to understand if a
>> native constructor can be used with `new` or not.
>>
>> BigInt("5555555555555555555555555500003");
>> 5555555555555555555555555500003n
>>
>> new BigInt("5555555555555555555555555500003");
>> VM51:1 Uncaught TypeError: BigInt is not a constructor
>>
>>
> ```
> typeof(5n)
> "bigint"
> ```
>
> Uint8Array([])
>> VM54:1 Uncaught TypeError: Constructor Uint8Array requires 'new'
>>
>> new Uint8Array([])
>> Uint8Array []
>>
>> Without that knowledge, any attempt to even think about a solution that
>> would scale not only with BigInt but with everything else, is kinda futile.
>>
>> Best Regards.
>>
>>
>>
>>
>>
>>
>> On Sun, Jul 15, 2018 at 8:27 AM Anders Rundgren <
>> anders.rundgren.net at gmail.com> wrote:
>>
>>> On 2018-07-15 08:17, J Decker wrote:
>>> <snip>
>>> > If you want to use BigInt with JSON you have to serialize it
>>> yourself:
>>> >
>>> > Yes; and I did forget to mentions erilaization side but the serlizer
>>> could do an additional type check and emit and appropriate thing.
>>>
>>> It is the "appropriate thing" that is problem; the rest is trivial.
>>>
>>> Anders
>>>
>>> > I thought the replacer could be used- but the output of replacer would
>>> have to type check to see if it's a bigint too....
>>> > https://github.com/v8/v8/blob/master/src/json-stringifier.cc#L305
>>> case BIGINT_TYPE: hmm and digging some more there's lots of eexcpetions
>>> thrown...
>>> >
>>> > does Number( "5n" ) ? result in a bigint? No....
>>> > ```
>>> > Number( "5n" )
>>> > NaN
>>> > var a = 5n
>>> > a
>>> > 5n
>>> > ```
>>> >
>>> >
>>> > var small = BigInt(5n);
>>> > var big = BigInt(5555555555555555555555555500003n);
>>> > JSON.stringify([big.toString(),small.toString()]);
>>> >
>>> > which generates ["5555555555555555555555555500003","5"]
>>> >
>>> > Anders
>>> >
>>> > > var small = 5n;
>>> > > var big = 5555555555555555555555555500003n;
>>> > >
>>> > > n suffix as from
>>> > > https://github.com/tc39/proposal-bigint
>>> > >
>>> > > JSON Number serialization has apparently reached a new
>>> level (of confusion).
>>> > >
>>> > > Personally I don't see the problem. XML did just fine
>>> without hard-coded data types.
>>> > >
>>> > > The JSON type system is basically a relic from JavaScript.
>>> As such it has proved to be quite useful.
>>> > > However, when you are outside of that scope, the point with
>>> the JSON type system gets pretty much zero since you anyway need to map
>>> extended types.
>>> > >
>>> > > Oracle's JSON-B solution which serializes small values as
>>> Number and large values as String rather than having a unified
>>> serialization based on the underlying data type seems like a pretty broken
>>> concept although indeed fully conforming to the JSON specification. "Like
>>> the Devil reads the Bible" as we say in Scandinavia :-)
>>> > >
>>> > > Adding a couple of double quotes is a major problem? If
>>> so, it seems like a way more useful project making quotes optional for keys
>>> (named in a specific way), like they already are in JavaScript.
>>> > >
>>> > > Yeah, and of course adding support for comments.
>>> > >
>>> > >
>>> > > I'd rather not see numbers converted to strings; that would be
>>> required to allow application handling of values; at a layer higher than
>>> JSON core itself. It is nice that JSON keeps numbers as numbers and
>>> strings as strings without needing intimite knowledge about the actual
>>> 'types' they end up in.
>>> > >
>>> > > Comparing numeric length would be a half/useless solution since
>>> bigints are required to interop with other bigints only; so small numbers
>>> couldn't be 'guessed' and the application would have to provide a reviver.
>>> > >
>>> > >
>>> > >
>>> > > Anders
>>> > >
>>> > > _______________________________________________
>>> > > es-discuss mailing list
>>> > > es-discuss at mozilla.org <mailto:es-discuss at mozilla.org> <mailto:
>>> es-discuss at mozilla.org <mailto:es-discuss at mozilla.org>>
>>> > > https://mail.mozilla.org/listinfo/es-discuss
>>> > >
>>> > >
>>> > >
>>> > > _______________________________________________
>>> > > es-discuss mailing list
>>> > > es-discuss at mozilla.org <mailto:es-discuss at mozilla.org>
>>> > > https://mail.mozilla.org/listinfo/es-discuss
>>> > >
>>> >
>>> >
>>> > On Sat, Jul 14, 2018 at 9:23 PM Anders Rundgren <
>>> anders.rundgren.net at gmail.com <mailto:anders.rundgren.net at gmail.com>>
>>> wrote:
>>> >
>>> > On 2018-07-15 04:27, J Decker wrote:
>>> > >
>>> > >
>>> > > On Sat, Jul 14, 2018 at 1:36 AM Anders Rundgren <
>>> anders.rundgren.net at gmail.com <mailto:anders.rundgren.net at gmail.com>
>>> <mailto:anders.rundgren.net at gmail.com <mailto:
>>> anders.rundgren.net at gmail.com>>> wrote:
>>> > >
>>> > > var small = BigInt("5");
>>> > > var big = BigInt("5555555555555555555555555500003");
>>> > > JSON.stringify([big,small]);
>>> > > VM330:1 Uncaught TypeError: Do not know how to serialize a
>>> BigInt
>>> > > at JSON.stringify (<anonymous>)
>>> > > at <anonymous>:1:6
>>> > >
>>> > >
>>> > > is BigInt the only way to create a BigInt ? Or did they also
>>> implement the 'n' suffix, which I noted here
>>> https://github.com/tc39/proposal-bigint/issues/24#issuecomment-392307848
>>> would easily distinguish bigint from other numbers; and be easy to add on
>>> the parsing side; and call BigInt(xxx) instead of Number(xxx).
>>> >
>>> > This problem is related to the BigInt object itself. If you
>>> create such using the 'n' notation you get the same result.
>>> >
>>> > If you want to use BigInt with JSON you have to serialize it
>>> yourself:
>>> >
>>> > var small = BigInt(5n);
>>> > var big = BigInt(5555555555555555555555555500003n);
>>> > JSON.stringify([big.toString(),small.toString()]);
>>> >
>>> > which generates ["5555555555555555555555555500003","5"]
>>> >
>>> > Anders
>>> >
>>> > > var small = 5n;
>>> > > var big = 5555555555555555555555555500003n;
>>> > >
>>> > > n suffix as from
>>> > > https://github.com/tc39/proposal-bigint
>>> > >
>>> > > JSON Number serialization has apparently reached a new
>>> level (of confusion).
>>> > >
>>> > > Personally I don't see the problem. XML did just fine
>>> without hard-coded data types.
>>> > >
>>> > > The JSON type system is basically a relic from JavaScript.
>>> As such it has proved to be quite useful.
>>> > > However, when you are outside of that scope, the point with
>>> the JSON type system gets pretty much zero since you anyway need to map
>>> extended types.
>>> > >
>>> > > Oracle's JSON-B solution which serializes small values as
>>> Number and large values as String rather than having a unified
>>> serialization based on the underlying data type seems like a pretty broken
>>> concept although indeed fully conforming to the JSON specification. "Like
>>> the Devil reads the Bible" as we say in Scandinavia :-)
>>> > >
>>> > > Adding a couple of double quotes is a major problem? If
>>> so, it seems like a way more useful project making quotes optional for keys
>>> (named in a specific way), like they already are in JavaScript.
>>> > >
>>> > > Yeah, and of course adding support for comments.
>>> > >
>>> > >
>>> > > I'd rather not see numbers converted to strings; that would be
>>> required to allow application handling of values; at a layer higher than
>>> JSON core itself. It is nice that JSON keeps numbers as numbers and
>>> strings as strings without needing intimite knowledge about the actual
>>> 'types' they end up in.
>>> > >
>>> > > Comparing numeric length would be a half/useless solution since
>>> bigints are required to interop with other bigints only; so small numbers
>>> couldn't be 'guessed' and the application would have to provide a reviver.
>>> > >
>>> > >
>>> > >
>>> > > Anders
>>> > >
>>> > > _______________________________________________
>>> > > es-discuss mailing list
>>> > > es-discuss at mozilla.org <mailto:es-discuss at mozilla.org> <mailto:
>>> es-discuss at mozilla.org <mailto:es-discuss at mozilla.org>>
>>> > > https://mail.mozilla.org/listinfo/es-discuss
>>> > >
>>> > >
>>> > >
>>> > > _______________________________________________
>>> > > es-discuss mailing list
>>> > > es-discuss at mozilla.org <mailto:es-discuss at mozilla.org>
>>> > > https://mail.mozilla.org/listinfo/es-discuss
>>> > >
>>> >
>>>
>>> _______________________________________________
>>> es-discuss mailing list
>>> es-discuss at mozilla.org
>>> https://mail.mozilla.org/listinfo/es-discuss
>>>
>> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
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