JSON Basics

What is JSON?

JSON (JavaScript Object Notation) is a human-readable data serialization format that is commonly used for configuration files and data exchange. It is based on the JavaScript programming language and is easy to read and write.

JSON Document Structure

A JSON document consists of one or more JSON objects, which are enclosed in curly braces {}. Each object contains key-value pairs, where the key is a string enclosed in double quotes "", followed by a colon :, and the value can be a string, number, boolean, array, or another object. The key-value pairs are separated by commas.

JSON Objects and Data Types

A JSON object is a collection of key-value pairs, where the key is a string and the value can be a string, number, boolean, array, or another object. JSON supports the following data types:

• String: A sequence of characters enclosed in double quotes "".
• Number: A numeric value, which can be an integer or a floating-point number.
• Boolean: A logical value that can be true or false.
• Array: An ordered list of values enclosed in square brackets [].
• Object: A collection of key-value pairs enclosed in curly braces {}.
• Null: A special value that represents null or an empty value.
• Nested Objects: Objects can contain other objects as values.
• Nested Arrays: Arrays can contain other arrays or objects as values.
• Mixed Data Types: JSON allows mixing different data types within an object or array.

JSON String, Number, Null and Boolean Example:

{
  "name": "John Doe",  //string
  "age": 30,  //number
  "is_student": false  //boolean
  "null_value": null  //null
}

JSON Array Example:

{
  "fruits": ["apple", "banana", "orange"]  //array
}

JSON Object Example:

{
  "person": { //object
    "name": "John Doe", //string
    "age": 30, //number
    "is_student": false //boolean
  }
}

JSON Nested Object Example:

{
  "person": { //object
    "name": "John Doe", //string
    "age": 30, //number
    "is_student": false, //boolean
    "address": { //nested object
      "street": "123 Main St", //string
      "city": "Anytown", //string
      "state": "NY", //string
      "zip": "12345" //string
    }
  }
}

JSON Nested Array Example:

{
  "person": { //object
    "name": "John Doe", //string
    "age": 30, //number
    "is_student": false, //boolean
    "hobbies": ["reading", "hiking"] //nested array
  }
}

JSON Mixed Data Types Example:

{
  "person": { //object
    "name": "John Doe", //string
    "age": 30, //number
    "is_student": false, //boolean
    "hobbies": ["reading", "hiking"], //array
    "address": { //nested object
      "street": "123 Main St", //string
      "city": "Anytown", //string
      "state": "NY", //string
      "zip": "12345" //string
    }
  }
}

Comments in JSON

JSON does not support comments.

JSON Parsers

To validate and format JSON data, you can use online parsers. My favorite online JSON parser is codebeautify.org

Conclusion

JSON is a popular data serialization format due to its simplicity and readability. Understanding the basic structure of JSON objects and data types is essential for working with JSON files effectively. Good luck!