How to make comment in JSON file

comments-trick.json

{
    "//field": "These 'double quote' 'double quote' are used as comments, because JSON doesnt' allow comment",
    "field": {},
    "#another-field": "Another comment",
    "another-field": {},
    "/*stuff": "Be careful to use them when you have full control of the content :)",
    "stuff": [],
    "bla": "bla"
}

None of these is how I would have done it,
I would have gone for something like this instead:

{
    "Comments": [
        "Lorem ipsum dolor sit amet,",
        "consectetur adipiscing elit.",
        "Suspendisse vitae risus ligula.",
        "Fusce vel urna turpis."
    ]
}

Then you won't have to think about making identifiers for every line, and it validates.

JSON 5 (https://json5.org/) does support comments. However, support for it is limited. E.g. PHP does not support it yet.

You can use:

/*
{
"Comments": [
"Lorem ipsum dolor sit amet,",
"consectetur adipiscing elit.",
"Suspendisse vitae risus ligula.",
"Fusce vel urna turpis."
]
}
*/

other options
put all the comment in the key :-)
there should be less duplicates problems
ex

{ 
  "// this is fun":"",
  "// this is also fun": "",
  "whatever": {
    "// other scope": "",
    "// this is fun": ""
  },
  "port": 8090, "// can't use native port":""
}

I'm also looking for this.

Because JSON is a subset of YAML, # should be used as comment character. IMHO :-) but as with everything one could argue about it
The YAML port: 8090 #can't use native port
could be converted to
a) "port": 8090, "#can't use native port":""
b) "port": 8090, "#":"can't use native port"

Change the file extension to .json5 and you can haz comments 🙂

try JSON5 or JSONC

https://json5.org/

https://code.visualstudio.com/docs/languages/json#_json-with-comments

I found it

Hjson, at https://hjson.github.io/, works better for me than JSON5. YMMV.

Its Python module has been maintained more recently and its documentation shows the syntax of multiline comments as well as #-based comments.

You can create a special key in your JSON Mapquest Directions object to store comments. This key would be ignored by any JSON parsers that don't use it, but it allows you to include notes.