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Megha M
Megha M

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What is JSON.stringify()? A Beginner’s Guide with Examples

#json #javascript #learntocode

When building modern web applications, working with JavaScript objects is inevitable. But what happens when you need to send data to a server, store it locally, or debug it in a readable format?

That’s where JSON.stringify() comes into play — a powerful method that transforms JavaScript objects into JSON strings. In today’s blog, we’ll explore what it does, how it works, and how to use it like a pro.

What is JSON.stringify()?

JSON.stringify() is a built-in JavaScript method that converts a JavaScript object, array, or value into a JSON-formatted string.

Syntax

JSON.stringify(value, replacer, space);

Why Use JSON.stringify()?

  • Sending Data to APIs: Most APIs accept JSON-formatted data.
  • Saving to Local Storage: localStorage and sessionStorage only store strings.
  • Debugging: Easily inspect object structure in a readable format.

Getting Started with an Example

const user = { name: "Megha", age: 25, isMember: true }; const jsonString = JSON.stringify(user); console.log(jsonString);
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Output:

{"name":"Megha","age":25,"isMember":true}
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Working with Nested Objects

const product = { id: 101, name: "Saree", details: { color: "Red", size: "Free" } }; console.log(JSON.stringify(product));
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Output:

{"id":101,"name":"Saree","details":{"color":"Red","size":"Free"}}
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Pretty Printing with space:

console.log(JSON.stringify(product, null, 2));
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Output:

{ "id": 101, "name": "Saree", "details": { "color": "Red", "size": "Free" } }
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Filtering Properties with replacer

const user = { name: "Megha", age: 25, password: "secret" }; const filteredJSON = JSON.stringify(user, ["name", "age"]); console.log(filteredJSON);
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Output:

{"name":"Megha","age":25}
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What JSON.stringify() Ignores

const data = { name: "Test", date: new Date(), sayHello: function () { return "Hello!"; }, something: undefined }; console.log(JSON.stringify(data));
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Output:

{"name":"Test","date":"2025-07-30T02:19:04.000Z"}
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Final Thoughts

JSON.stringify() is an essential tool in every JavaScript developer’s toolkit. It allows you to:

  • Serialize complex objects
  • Communicate with APIs
  • Store structured data
  • Clean up logs for debugging

Next time you need to convert your JavaScript objects into a string — remember, JSON.stringify() has you covered!

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