[Format] Token value - string, number, array, object?

[kevinmpowell]

JSON supports string, number, array and object as data types. Which of these do we want to support for token values.

String:

{
  colorTextPrimary: {
    value: '#000000'
  }
}

Number:

{
  durationDefault: {
    value: 10
  }
}

Array:

{
  breakpoints: {
    value: ['320', '640', 1080]
  }
}  

Object:

{
  textHeadingLevel1: {
    value: {
      fontSize: 32
      fontWeight: 700
      lineHeight: 1.5
    }
  }
}

I suspect we'll need to support all four data types.

[c1rrus]

I'd say a token's value can potentially be any of the JSON types (also including boolean and null).

Of course, each of the DTCG types we define in our spec (color, dimension, duration, etc.) specifies exactly how values of that type must be formatted. So, when using those types (which I suspect most tokens would), we are narrowing down which underlying JSON type(s) those values can be. E.g. color values can only ever be JSON strings.

However, types we add in future and/or iterations of the current types may well be built on the full range of JSON types, so I see no reason to artificially limit their use.

Besides, this rule from the Types section pretty much necessitates all JSON types being available:

If the type property is absent, tools MUST treat values as one of the basic JSON types and not attempt to infer any other type from the value.

[kevinmpowell]

@c1rrus I agree. I don't think we need to belabor this topic. I'll get a PR together to update the spec with this information so we can close this issue out.