Newtonsoft.json: Support JSON5

[Alxandr]

JSON5 is a proposed extension to JSON that brings ES5 enhancements to its syntax. It remains a strict subset of JavaScript, adds no new data types, and is a strict superset of existing JSON. - json5

Json5 basically adds support for comments, un-quoted keys, and trailing comas. In addition to:

• Strings can be single-quoted.
• Numbers can be hexadecimal (base 16).
• Numbers can begin or end with a (leading or trailing) decimal point.
• Numbers can include Infinity and -Infinity.
• Numbers can begin with an explicit plus (+) sign.

I'm not saying that by default it should just be parsed, but if a option to the parser/deserializer could be provided that allowed these features, that would be really awesome :).

And given that it's a strict superset of existing JSON, this should not break anything, even if people were to run with the new flag turned on for old JSON files.

[Alxandr]

After reading through most of your feature-list on http://james.newtonking.com/json, it would seem that a lot of the requested features are already present in Newtonsoft.Json. What you already support are (according to your own list):

• Handles NaN, Infinity, -Infinity and undefined
• Unquoted property names support
• Supports reading and writing comments
• Single or double quote JSON content

[JamesNK]

I think the only things to do are:

• Numbers can begin or end with a (leading or trailing) decimal point.
• Numbers can begin with an explicit plus (+) sign.

[JamesNK]

I've thought about this and if JSON5 catches on as a thing I'll do more to support it then.

[marcselman]

@JamesNK What's you stance on this now, two years later?
Especially supporting comments make documenting JSON files alot easier.

[JamesNK]

JSON5 hasn't caught on as a thing.
I already support comments.

[marcselman]

Oh, I did not know that. It's not that easy to find actually.
Thanks.

[kasajian]

I'm not sure how we're measuring "catching on as a thing" (legitimate question), but I just noticed that the json5 node package was downloaded 3.5 million times this week. The trend shows steady progress since the last comment here in December of 2016:

Trend: http://www.npmtrends.com/json5

Looks like it'll be 4.5M downloads per week soon.

stats:
https://gist.github.com/anvaka/8e8fa57c7ee1350e3491

Might be nice to have it as a check-mark item.

[Mardoxx]

Pretty sure it's caught on as a thing!

[Fireboyd78]

@JamesNK Came here to say it's definitely caught on as a thing! We're working on a project in Unity where there's different configuration files, and JSON5 is about the closest thing you can get to an actual object's representation in memory:

{
  VehicleInfo : {
    Name : 'Big Truck',
    Colors : [
      'Rusted Out',
    ],
    Flags : 0x7, // is_player | is_unlockable | is_heavy
    TopSpeed : 89.9,
    Horsepower : 457.925, // leave this alone, jeff!!
    Mass : 12500.0,
  }
}

As you would imagine, VehicleInfo would be a class containing those particular members with easy to deduce types.

I actually wrote another data storage format for exactly this purpose, which looks like this:

VehicleInfo : {
  Name = "Big Truck"
  // 'Colors' is a string list, so we use a string tuple instead of a generic array
  Colors = (
    "Rusted Out",
  )
  Flags = 0x7 // is_player | is_unlockable | is_heavy
  TopSpeed = 89.9f
  Horsepower = 457.925f // leave this alone, jeff!!
  Mass = 12500.0f
}

While serialization wasn't originally planned, it somehow ended up turning into a C-like JSON format...and the code is a mess and just doesn't make sense.

Instead of reinventing the wheel, JSON5 perfectly aligns with our needs. I see JSON used _everywhere_ these days, and I'm sure a lot of people would happily use JSON5 without needing to download a different library, and needing only to make very few code changes to support it.

Tldr;
JSON5 is amazing for game developers, please consider adding support!