JavaScript JSON stringify() Method

The JSON.stringify() method in JavaScript is used to convert JavaScript objects into a JSON string. This method takes a JavaScript object as input and returns a JSON-formatted string representing that object.

Syntax:

JSON.stringify(value, replacer, space);

Parameters:

• value: It is the value that is to be converted into a JSON string.
• replacer: It is an optional parameter. This parameter value can be an altering function or an array used as a selected filter for the stringify. If the value is empty or null then all properties of an object are included in a string.
• space: It is also an optional parameter. This argument is used to control spacing in the final string generated using the JSON.stringify() function. It can be a number or a string if it is a number then the specified number of spaces are indented to the final string and if it is a string then that string is (up to 10 characters) used for indentation.

Return Value: Returns a string for a given value.

JavaScript JSON stringify() Method Examples

Example 1: Converting JavaScript Object to JSON String

The code demonstrates how to convert a JavaScript object obj into a JSON string using JSON.stringify(). The resulting JSON string represents the properties of the object in a serialized format.

const value = {
    Company: "GeeksforGeeks",
    Estd: 2009,
    location: "Noida"
};
const result = JSON.stringify(value);
console.log("value of result = " + result);

value of result = {"Company":"GeeksforGeeks","Estd":2009,"location":"Noida"}

Example 2: Deep Copying JavaScript Object with JSON.stringify() and JSON.parse()

The code creates an object obj with nested properties. JSON.stringify() converts obj to a JSON string, then JSON.parse() parses it back to an object obj2. Modifying obj2 doesn't affect obj, illustrating deep copying.

let obj = {
    name: "GFG",
    add: {
        country: "India",
        state: {
            code: "JS",
            topic: "stringify"
        }
    }
}

let obj2 = JSON.parse(JSON.stringify(obj));
obj2.add.state.topic = "stringify json object";
console.log(obj);
console.log(obj2);

{
  name: 'GFG',
  add: { country: 'India', state: { code: 'JS', topic: 'stringify' } }
}
{
  name: 'GFG',
  add: {
    country: 'India',
    state: { code: 'JS', topic: 'stringify json object' }
  }
...

Example 3: Converting Array to JSON String

The code converts the array value into a JSON string using JSON.stringify(). The resulting string result is logged along with its type. This demonstrates how JSON.stringify() converts JavaScript data types into JSON strings.

let value = ["Logan", 21, "Peter", 24];
let result = JSON.stringify(value);
console.log("value of result = " + result);
console.log("type of result = " + typeof result);

value of result = ["Logan",21,"Peter",24]
type of result = string

We have a complete list of Javascript JSON methods, to check those please go through Javascript JSON Complete Reference article.

Supported browsers:

• Chrome 4.0
• Firefox 3.5
• Microsoft Edge 12.0
• Opera 11.0
• Internet Explorer 8.0
• Safari 4.0