Submitted for your approval, JSOX

Mike Samuel mikesamuel at
Wed Sep 19 15:14:38 UTC 2018

TC39 is not really a place to spec out new transport formats.

You proposed builtin support for JSON5 <>
last year.
JSON5 was speced and had some adoption but that was controversial because
JSON5 was not nearly as widely used as JSON.
This seems to offer more obvious benefits over JSON than JSON5, but it
doesn't yet approach the adoption threshold.


IIUC, type tags can only reference builtin types with well-understood
semantics like Date and typed arrays or structs with default values defined
in the same JSON input.
No type referenced by JSON can be or extend a type defined by application

If that's not the case, please keep in mind though that deserialization
schemes that allow an external input to specify which types to construct
makes it easy for an attacker to forge objects that code might treat as
privileged because it assumes all instances are created internally.
"Malformed data or unexpected data could be used to abuse application
logic, deny service, or execute arbitrary code, when deserialized."
See also "History of Java deserialization vulnerabilities" at

This already happens with plain JSON
so anything that allows external inputs to specify which internal types to
construct would have to include a "Security Considerations" section that
explains how this could be safely used by code that assumes that `if (x
instanceof InternalType)` then x came from internal code that made a
good-faith effort to only pass appropriate inputs to `new

On Tue, Sep 18, 2018 at 5:22 PM J Decker <d3ck0r at> wrote:

> (Thank you Rod Sterling)
> But seriously, I'd like to submit, for serious consideration, JSOX -
> JavaScript Object eXchange format.  It inherits all JSON syntax such that
> it is able to process any existing JSON.
> I'm, at this point, open to changing anything (or even omitting things),
> including the name.
> JSON is great.  JSON has some limits, and criticisms... JS/ES Grew , but
> JSON has to stay the same, similarly with whatever comes next I'd imagine.
> So a primary goal is to encode and decode ES6 objects for transport with a
> simple API such as JSOX.parse( object ), and JSOX.stringify( jsoxString ).
> But also keep with the simplicity of JSON,
> so it can be used in human readable circumstances.
> Types that are now (or soon) native to ES such as TypedArrays (binary
> data), BigInt types, and even the existing Date type, do not transport with
> JSON very well.  They become a non-identifable string, that requires extra
> code involving knowledge of the structure of the data being transferred to
> be able to restore the values to Date(), BigInt(), et al.
> So a few weeks ago I started considering what else, beyond these simple
> modifications might also be useful, or address criticisms of JSON.
> Handling the above types is really a trivial modification to most JSON
> parsers.  Each of the following modifications is really only a very slight
> change to behavior; although implementing typed-objects does initially
> involve changing error handling into identifer-fallback handling.
> I initially argued, that defining a object prototype
> 'card(name,address,zipcode,created)' which removes the redundant data for
> every following reference, (and is good, just for data reduction, which was
> argued 'gzip').  A JSON representation might be
> `{"name":"bob","address":"123
> street","zipcode":"55555","created":1537304820} where if have a large
> number of the same record the same 'name':,'address':, etc is repeated in
> every record.  Where a typed-object's value in JSOX could be
> `card{:"bob","123 street","55555",2018-09-18T21:07:00Z}`.  All objects that
> are revived as typed-objects share the same prototype, and before parsing,
> the prototypes to be used may be specified.  The amount of data to process
> is reduced, perhaps to a significant degree.
> So <Identifer> '{' is about typed-objects.  This construct is not allowed
> in JSON.  But that then leads to <Identifier> '['  - typed arrays, arrays
> don't really have redundant data potential like objects, but there are
> TypedArrays in ES.  There is no way to define a type of an array, but
> hardcoded types like 'ab', 'u8', 'ref' are used to revive binary data.  The
> bytes of the backing ArrayBuffer are encoded to base64, and included within
> '[' and ']' without quotes; using the brackets as quotes.
> A JSOX typed array is the 'ref' type.  A reference to another location in
> the current object can be specified, which allows encoding cyclic
> structures.
> (Initial public reaction was not very helpful, but probably that's the
> fault of how it was introduced?)
> There was plenty of 'why not [YAML/BSON/protobufs/(I don't think anyone
> said XML)/...]'  and the answer is simply, because none of those read JSON,
> or have as simple of an API. (amongst other reasons that JSON is already a
> solution for compared to those mentioned)
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