JSON (JavaScript Object Notation)

JSON is the universal language of the web. It's how servers speak to browsers, and how apps save data. If you want to build web apps, you must know JSON.

1. What is JSON? 📄

What is it? JSON stands for JavaScript Object Notation. It is a lightweight text format for storing and transporting data.

Why use it?

• Universal: It's readable by almost every programming language (Python, Java, C++, etc.), not just JavaScript.
• Lightweight: It uses very little space compared to XML.
• Easy: It looks almost exactly like a JavaScript object.

How it works: It's essentially a string that looks like code.

2. Converting Object to JSON (stringify) 📤

Scenario: You have data in your app (an object) and you want to send it to a server. You can't send raw memory; you need to turn it into a text string first.

Method: JSON.stringify(object)

3. Converting JSON to Object (parse) 📥

Scenario: You receive data from a server (as a string). You need to turn it back into a JavaScript object so you can use it (e.g., data.name).

Method: JSON.parse(string)

4. JSON Rules & Limitations ⚠️

JSON is strict! It is not exactly the same as JavaScript objects.

1. Keys must be double-quoted: {"key": "value"} (Not {key: "value"}).
2. No Functions: JSON cannot store functions.
3. No undefined: Properties with undefined values are removed.
4. No Comments: You cannot add comments in JSON.

5. Practical Use: LocalStorage 💾

Browsers have a built-in database called localStorage. It only saves strings. So, to save objects, we use JSON!

Quiz

Key Takeaways

✅ JSON is the standard for web data.
✅ JSON.stringify(): Object ➡️ String (Sending data).
✅ JSON.parse(): String ➡️ Object (Receiving data).
✅ Keys must have double quotes "".
✅ No functions or undefined allowed.

What's Next?

Now that we can handle data, let's learn how to handle Time with the Date object!

Keep coding! 🚀