Javascript: Explain JSON.stringify() in Javascript

 Q. Explain JSON.stringify() in Javascript

 

JSON.stringify() is a method in JavaScript that converts a JavaScript object or value into a JSON string. JSON stands for JavaScript Object Notation, and it's a lightweight data-interchange format that's easy for humans to read and write and easy for machines to parse and generate.

Here's how JSON.stringify() works:

1. If the input value is an object (including arrays, dates, and plain objects), JSON.stringify() will serialize it into a JSON string.
2. If the input value is not an object (like a string, number, boolean, or null), it will be coerced into its corresponding primitive value, and that value will be returned.
3. If the input value is undefined, a function, or a symbol, it will be excluded from the resulting JSON string (or replaced with null if it's a property value within an object).

Here's a simple example:

javascript
const obj = {
  
name: "John",
  
age: 30,
  
isAdmin: true,

  hobbies: ["reading", "coding", "hiking"],

  address: {
    city: "New York",
    zip: "10001"
  }

};


const jsonString = JSON.stringify(obj);

console.log(jsonString);

This will output:

Result
{"name":"John","age":30,"isAdmin":true,"hobbies":["reading","coding","hiking"],"address":{"city":"New York","zip":"10001"}}

You can also provide a "replacer" function or an array of property names to specify which properties should be included or how they should be transformed during serialization. Additionally, you can specify a "space" parameter to add whitespace for improved readability of the resulting JSON string.

javascript
const obj = {
  
name: "John",

  age: 30,

  isAdmin: true,
  
hobbies: ["reading", "coding", "hiking"],

  address: {
    city: "New York",
    zip: "10001"
  }

};


const jsonString = JSON.stringify(obj, ['name', 'hobbies'], 2);
console.log(jsonString);

This will output:

Result
{
  "name": "John",
  "hobbies": [
    "reading",
    "coding",
    "hiking"
  ]
}

This is particularly useful when you want to exclude certain properties or control the structure of the resulting JSON string.