Is a primitive type considered JSON?

Question

Most place the JSON is in format like

{
    color: \"red\",
    value: \"#f00\"
}

Or

[  
    { color: \"red\",     value: \"#f0         


        

Answer 1

The relevant RFC is RFC 7159, not RFC 4627. RFC 4627 is "informational". RFC 7159 is "standards track"; it explicitly obsoletes RFC 4627.

Request for Comments: 7159                                  Google, Inc.
Obsoletes: 4627, 7158                                         March 2014
Category: Standards Track
ISSN: 2070-1721

In the text of RFC 7159, you'll find this.

13.  Examples

   This is a JSON object:

      {
        "Image": {
            "Width":  800,
            "Height": 600,
            "Title":  "View from 15th Floor",
            "Thumbnail": {
                "Url":    "http://www.example.com/image/481989943",
                "Height": 125,
                "Width":  100
            },
            "Animated" : false,
            "IDs": [116, 943, 234, 38793]
          }
      }
   [snip]
   Here are three small JSON texts containing only values:

   "Hello world!"

   42

   true

Answer 2

{ "astring" } is not valid JSON and neither is "astring" or astring, as we need both a key and a value, e.g. { KEY : VALUE } where KEY is always a string and VALUE can be a string, number, boolean, or null.

From the spec:

Yes, as the spec says, JSON can be a top level primitive value without an object wrapping it. – Andy Ray

If I understood it correctly, that comment is not correct. Valid JSON is never a top-level primitive value by itself. If you're still confused, this should clear things up:

2. JSON Grammar

   A JSON text is a sequence of tokens. The set of tokens includes six structural characters, strings, numbers, and three literal names.

   A JSON text is a serialized object or array.

   JSON-text = object / array

   These are the six structural characters:

   begin-array = ws %x5B ws ; [ left square bracket

   begin-object = ws %x7B ws ; { left curly bracket

   end-array = ws %x5D ws ; ] right square bracket

   end-object = ws %x7D ws ; } right curly bracket

   name-separator = ws %x3A ws ; : colon

   value-separator = ws %x2C ws ; , comma

   Insignificant whitespace is allowed before or after any of the six structural characters.

Answer 3

FWIW, here's output from the command line JSON parser prgram jq:

$ echo "{ foo }" | jq .
parse error: Invalid literal at line 1, column 6

$ echo "{ \"foo\" }" | jq .
parse error: Objects must consist of key:value pairs at line 1, column 9

$ echo "\"foo\"" | jq .
"foo"

I don't have access to other parser at the moment.