On 2018-03-19 07:32, Michał Wadas wrote:
Yeah, there are workarounds for passing bigints.
Unfortunately, it's workaround, and it doesn't solve the problem -
certain valid JSONs can't be properly used in ECMAScript without writing JSON parser in user land.
Hi Michal,
I wouldn't call it a workaround.
The idea that there must be a native data type in a message format for each
data type you can come up with has huge real-world limitations. Physical
address descriptors (street, zip, state, etc), don't have native JSON
counterpart either to take a fully valid example from another application area.
Using an external (with respect to the parser), mapping schema [1,2] addresses
these problems in a fully universal and extensible manner.
toJSON seems to do a good job in the other direction.
The importance of JSON "Number" is exaggerated. In the systems I work with (Payments),
you hardly find a single instance of "Number". No, it doesn't even work for expressing
money!
Anders
1] Ultra simple/manual: new BigNum(obj.sizeOfTheUniverseInCubicMeters);
2] Sophisticated: JSON.parseWithSchema(schema, jsonData);
On Mon, 19 Mar 2018, 03:33 Anders Rundgren, <[email protected]
<mailto:[email protected]>> wrote:
On 2018-03-19 02:37, Anders Rundgren wrote:
> On 2018-03-19 02:33, Michał Wadas wrote:
>> Fact: JSON allows arbitrary precision numbers.
>> Problem: JavaScript is unable to express these numbers.
>>
>> Proposed solution: introduce JSON.safeParse. This method will work as
JSON.parse, but throwing on values that can't be accurately represented by IEEE 754
64-bit float.
>>
>> Alternative: allow user to specify number class - eg. by adding options object
with optional method "parseNumber", overwriting default behaviour of using builtin
number type.
>>
>> Any thoughts on this?
>
> Yes, it is a SUPERBAD idea.
Pardon my unnecessary dismissive response. A more constructive response
would be:
This is "approximately" the de-facto standard for dealing with BigNums and
tons of other non-standard types.
var obj = JSON.parse("JSON formatted data");
var val = new BigNum(obj.sizeOfTheUniverseInCubicMeters);
JSON on the wire:
{
"sizeOfTheUniverseInCubicMeters": "3.45e+445454545454545776767676676"
}
When TC-39 introduces BigNums in ES, this is the most likely way they will
address this particular aspect.
Anders
>
> Anders
>
>>
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>
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