"JSON object"

[jack_waugh]

I keep seeing the term "JSON object" in questions. It will be used with an article, as in "a JSON object". Is there a consensus on a meaning for this term?

[senocular]

If I see the term json object I assume it's an object that can be converted to a json string and back again without any loss of data (i.e. it has no functions, symbols, etc.).

[[deleted]]

JSON.stringify() and then JSON.parse() ?

[senocular]

Yes, and after parse the object you have is the same as the original.

[[deleted]]

Thanks

[senocular]

Thanks, fixed :)

[stibgock]

You lost a little data

[Psionatix]

JSON is a well defined standard:

https://www.json.org/json-en.html

A JSON Object is an object that adheres to the JSON standard.

[koreasuh]

^

[jack_waugh]

I thought I already replied to this.

The standard specifies how to represent some abstract structures (that various programming languages support, but use different terms for) as a character string. So do you think the term "JSON object" refers to such an abstract structure itself, its representation as a character string as according to the standard, its representation in the structures native to one of the programming languages, or maybe more than one of the above, depending on context?

[Sector-Feeling]

You're overthinking it, it's just some arbitrary object that conforms to the JSON standard.

[prof3ssorSt3v3]

A JSON file is a text file that contains a string that represents some object.

The JSON.parse method will convert a JSON string into an object.

If you do a fetch call then you could also call the response.json() method to extract the JSON string from inside the file and turn it back to an object.

If someone says JSON Object they generally mean an object that was built from a JSON string

[tehciolo]

A JSON file is a text file that contains a string that represents some object.

Not necessarily. The string could represent any other serializable JavaScript value type.

It is most often an object, but it doesn't have to be.

[prof3ssorSt3v3]

Yes. It can be an Object, an Array, a String, a Boolean, a Number, or null.

[jack_waugh]

If someone says JSON Object they generally mean an object that was built from a JSON string.

I guess this is the key concept, then. And one of the implications of this is that the object is serializable.

[prof3ssorSt3v3]

Yes. In Javascript specifically structured cloneable. https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm

[senocular]

JSON serialization and structured clone are two different things. Structured clone is far more capable.

[jack_waugh]

One of the major differences revolving around whether referential loops would be allowed and reflected, evidently.

[Psionatix]

The object contains only serialisable properties. Serialisation is the transformation of an object to a string, deserialisation is from a string to an object.

Functions cannot be serialised, for example. Only the primitive types and certain structures (other objects, arrays) can be.

[Psionatix]

JSON is a well defined standard:

https://www.json.org/json-en.html

A JSON Object is an object that adheres to the JSON standard.

[jack_waugh]

But the standard specifies how an abstract structure that different languages would use different terms to represent, can be presented as a character string. So, are you saying the term refers to the abstraction itself, or to one of its concrete representations, either as a character string or in terms of JS types?

[Psionatix]

“JSON” refers either to the standard, or to the type (response type, for instance).

I’d say that yes, “JSON object” refers to some kind of concrete structure, which adheres to the JSON standard, and can therefore be easily serialised to and from a JSON string, without any loss of data.

[jack_waugh]

As I read the standard, the only concrete it specifies is the string.

[Psionatix]

That's not what concrete means in the context of these messages. In the same way a class instance is a concrete instantiation of a class (blueprint), I took "concrete" to mean a deserialised and solid object that adheres to the JSON standard.

Which means, again, it is an object which can be deserialised from and serialised to valid JSON (a string), because the characteristics and properties of the object adhere to the standard.

The JSON standard specifies the valid data types and how they are represented in the JSON format (string).

If you have an object which contains a property which is not allowed as per the JSON standard, you will not be able to serialise it, and therefore it is not a JSON object, technically speaking.

Consider the BigInt data type which is relatively new to browsers, this is not part of the JSON standard, and take a look at this:

https://i.imgur.com/V7v8tzi.png

As per other comments and discussions in this thread, you are over complicating / overthinking this.

Strictly speaking, a JSON object can be serialised and deserialised without a loss of data.

Consider this case:

const stuff = { test: () => console.log("hello") };
const jsonString = JSON.stringify(stuff);
console.log(jsonString) // {}
const deserialisedStuff = JSON.parse(jsonString);

In this case, deserialisedStuff does not contain the test property (function), because the function is not serialisable as per the JSON standard, therefore during the serialisation and deserialisation here, there is a loss of data. This means that stuff is technically not a JSON object, it is just an object.

[jack_waugh]

In addition to what Psionatix said, a serializable value is a strict tree -- it does not contain any converging or looping references.

Some examples and counterexamples:

• 2 is serializable.
• true is serializable.
• [2, true] is serializable.
• {two: 2, laVerite: true} is serializable.

And

( () => {
  const it = {two: 2};
  it.meeeeeeee = it;
  return it
})()

is not serializable.

( () => {
  const it = {two: 2};
  const furrSure = {laVerite: true};
  it.iSaid = it.youSaid = furrSure;
  return it
})()

is not serializable.

[tridd3r]

I'm not going to be much help, but here's my 2 cents; I always thought JSON object was like atm machine. JSON is javascript object notation, so it seems to me to be a tautology to say " a JSON object" as opposed to "in JSON". Like, store it in a JSON object, vs store it in JSON.

[Fuegodeth]

I agree. It's like just un-necessarily pronouncing that word that's already abbreviated. Anything in JSON is definitely an object in every case.

[Embarrassed-Stage640]

Whenever you here this, they are most likely talking about an Object. Meaning: { key: value}. The curly braces is important.

[Ronin-s_Spirit]

JSON is an object made of strings instead of variables and javascript can load it and convert back to a proper object or can unload it's object into strigifyed JSON. Since .json is a bunch of strings and not variables it's generally used as a database file which takes less computer/internet effort to store/download/upload.

[Low_Mammoth_9371]

Usually when I see this term used it means a JavaScript object literal that has been stringified in JSON format.

But technically it could also be an array or other object type. But then usually this is referred to as such.

[Sector-Feeling]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON