Basic Structure

JSON (JavaScript Object Notation) is a lightweight data format that's easy to read and write. The basic structure consists of key-value pairs.

{
    "key": "value"
}

Data Types

JSON supports several data types including strings, numbers, booleans, null, arrays, and objects.

{
    "string": "Hello, World!",
    "number": 42,
    "float": 3.14,
    "boolean": true,
    "null": null,
    "array": [1, 2, 3],
    "object": {
        "nested": "value"
    }
}

Arrays

Arrays in JSON are ordered collections of values, which can be of any type.

[
    "apple",
    "banana",
    "orange"
]

Nested Objects

JSON objects can contain other objects and arrays, allowing for complex data structures.

{
    "user": {
        "name": "John Doe",
        "age": 30,
        "address": {
            "street": "123 Main St",
            "city": "Boston",
            "state": "MA",
            "zip": "02108"
        },
        "hobbies": [
            "reading",
            "gaming",
            "coding"
        ]
    }
}

Common Use Cases

API Response

JSON is commonly used in API responses to structure data in a consistent format.

{
    "status": "success",
    "data": {
        "id": 1,
        "title": "Example Post",
        "content": "This is a sample post",
        "author": {
            "id": 1,
            "name": "John Doe"
        },
        "comments": [
            {
                "id": 1,
                "text": "Great post!",
                "user": "Alice"
            }
        ]
    }
}

Configuration

JSON is often used for configuration files due to its readability and structure.

{
    "app": {
        "name": "My App",
        "version": "1.0.0",
        "settings": {
            "theme": "dark",
            "language": "en",
            "notifications": true
        }
    }
}

Working with JSON in JavaScript

JavaScript provides built-in methods to work with JSON data. Here are the most common operations:

// Parse JSON string to object
const jsonString = '{"name": "John", "age": 30}';
const obj = JSON.parse(jsonString);

// Convert object to JSON string
const person = {
    name: "John",
    age: 30
};
const json = JSON.stringify(person);