Add 'json/flat' format

[dbanksdesign]

From the discussion on #58 , we want to add different types of JSON formatting for different purposes. This format should output a JSON string that only has 1 level where the keys are the property name and the value is the property value. For example, this style dictionary JSON:

{
  "size": {
    "font": {
      "small": { "value": "13px" },
      "medium": { "value": "15px" },
      "large": { "value": "17px" },
      "base": { "value": "{size.font.medium.value}" }
    }
  }
}

Would output this in the 'json/flat' formatter:

{
  "SizeFontSmall": "13px",
  "SizeFontMedium": "15px",
  "SizeFontLarge": "17px",
  "SizeFontBase": "15px"
}

You can have a look at how the other formatters are written to see how to write a formatter and where it should go.

Make sure to include proper jsdoc comments and unit test!

[ericbreno]

Looking into it, interesting!

[chazzmoney]

Merged, closing

[kerryj89]

When using json/flat it keeps the hyphens and I'm assuming other symbols. Is there a way to easily transform it to not include them and into camelCase so that we can simply import the json and do tokens.sizeFontSmall and not tokens['size-font-small']?

[jorenbroekema]

Yes, by adding a name transform that converts token names to camelCase

E.g.

{
  "source": [
    "tokens.json"
  ],
  "platforms": {
    "json": {
      "transforms": [
        "name/camel"
      ],
      "buildPath": "build/json/",
      "files": [
        {
          "destination": "vars.json",
          "format": "json/flat"
        }
      ]
    }
  }
}

Example