What is the difference between JSON and an object?

I assume that the reader has some basic knowledge of Javascript:

//así declaramos un objeto básico en Javascript
let objeto={ atributo: 'valor'}

They are not the same

JSON is the acronym for JavaScript Object Notation , it is a lightweight text format for data exchange. What does this mean? Well, if we see the following text

<lista-nodos>
  <nodo id="1">texto1</nodo>
  <nodo id="3">texto2</nodo>
  <nodo id="5">texto1</nodo>
</lista-nodos>

Every programmer is clear that this is a text in XML format . Well, JSON is nothing more than a different format but with the same function. The equivalent of that XML could be something like:

[
  { "id": "1", "valor": "texto1"},
  { "id": "3", "valor": "texto2"},
  { "id": "5", "valor": "texto1"}
]

As its name suggests, this notation is similar to what we would use in Javascript to create an object :

const datos=[
  { id: "1", valor: "texto1"},
  { id: "3", valor: "texto2"},
  { id: "5", valor: "texto1"}
];

datos.forEach(dato=> console.log('elemento:',dato.id,dato.valor))
console.info("tipo de dato=", typeof(datos))

But a JSON is, and here I am repeating myself, text :

//esto es un texto en formato JSON
const datosJson=`[
  { "id": "1", "valor": "texto1"},
  { "id": "3", "valor": "texto2"},
  { "id": "5", "valor": "texto1"}
]`;

console.log(datosJson);
console.info("tipo de dato=", typeof(datosJson))

The JSON format is somewhat more restrictive than Javascript code would be:

• All values ​​of type string must be enclosed in double quotes, single quotes are not allowed.
• Similarly, all keys (attribute names) must be enclosed in double quotes.
• It doesn't support any kind of comments (unlike XML, where we can use <!-- Comentarios-->)
• Numerical values ​​must be in decimal base, it does not admit leading zeros (which could think that the number is in octal base).
• Values ​​are not supported undefined.

And how do we transform the text into a manipulable object? And how do we do the reverse operation?

Using the following functions:

• JSON.parse(<texto>)It returns an object created from a string that is in JSON format.
• JSON.stringify(obj)It returns a string in JSON format with the attributes of the object obj. If objit has attributes that are functions, they will be ignored.

//texto con formato inválido
const datosJson=`[
  { "id": "1", valor: "texto1"},
  { "id": "3", valor: "texto2"},
]`;
try {
  const datos=JSON.parse(datosJson);
} catch(error) {
  console.log('Falla porque las claves valor no está entre comillas')
}
const datosJson2=`[
  { "id": 1, "valor": "texto1"},
  { "id": 3, "valor": "texto2"},
  { "id": 5, "valor": "texto1"}
]`;
//transformamos a objeto
const d=JSON.parse(datosJson2);
console.log(d[0].id);

//añadimos un elemento
d.push({id:4,valor:'otro texto'});

//transformamos el objeto de nuevo a JSON
console.log(JSON.stringify(d));

Therefore, although JSON originates from the Javascript language, it is nothing more than a way of sending data between applications, which will not necessarily be implemented with Javascript: any programming language can process a JSON (just like an XML) to obtain the needed information.

Two everyday examples of using JSON are:

• AJAX: When we send or receive data from a server, the information is usually sent as plain text, we cannot send an object as binary data if the language that receives it will not know how to interpret it (many times, when requesting resources from an API of third parties, we don't even know what programming language was used).
• Web Storage: When we want to save data in the user's browser, using the localStorageor the , the and sessionStoragemethods only work with the type , so it is necessary to transform the objects that we want to save to text.setItemgetItemstring

I would like to give a more colloquial answer, something you could give as an example to a non-programmer or beginner.

- Object: it is limited to the code, it is initialized and it is worked with the object during the execution of a program. The object will be formatted according to the semantic rules of the corresponding (object-oriented) language in which the code in which the objects are defined is written.

- JSON: is the 'file' that is used as input-output, to initialize or save states or values ​​of an object and as it is a 'standard', it has its own defined semantic rules. This standardization of the format makes JSON compatible across different programming languages.