What is JSON?

JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.

Why use JSON?

Human-Readable: JSON is easy to read and understand, making it accessible for developers and non-developers alike.
Lightweight: JSON is a lightweight format, which means it requires less bandwidth and storage compared to other formats like XML.
Language-Independent: JSON can be used with virtually any programming language, making it a versatile choice for data interchange.
Structured Data: JSON supports complex data structures, including nested objects and arrays, allowing for rich data representation.
Widely Supported: JSON is widely supported by web APIs and services, making it a standard choice for data exchange on the web.

Structure and Syntax

1. Primitive Types

JSON supports these primitive data types:

{
  "string": "Hello World",        // Text data
  "number": 42,                   // Integer
  "float": 3.14159,              // Decimal number
  "boolean": true,                // true or false
  "null": null                    // Null value
}

2. Arrays

Arrays are ordered collections of values:

{
  "empty": [],                    // Empty array
  "numbers": [1, 2, 3, 4, 5],     // Number array
  "strings": ["red", "green"],    // String array
  "mixed": [1, "hello", true],    // Mixed types
  "nested": [[1, 2], [3, 4]]      // Nested arrays
}

3. Objects

Objects are collections of key-value pairs:

{
  "person": {
    "name": "John Doe",
    "age": 30,
    "address": {
      "street": "123 Main St",
      "city": "Boston"
    }
  }
}

4. Complex Example

Real-world JSON often combines multiple types:

{
  "id": 1001,
  "active": true,
  "name": "Product X",
  "price": 99.99,
  "tags": ["new", "sale"],
  "stock": {
    "warehouse": 50,
    "retail": 10
  },
  "variations": [
    {
      "color": "red",
      "size": "M",
      "available": true
    },
    {
      "color": "blue",
      "size": "L",
      "available": false
    }
  ]
}

Common JSON Errors

1. Missing or Extra Commas

Commas must separate array elements and object properties, but shouldn't appear after the last item:

{
  "name": "John",   // Correct
  "age": 30,       // Correct
  "city": "Boston", // Extra comma - ERROR!
}

2. Single Quotes Instead of Double Quotes

JSON requires double quotes for strings:

{
  'name': 'John',  // ERROR! Single quotes not allowed
  "age": 30
}

3. Including Functions or Undefined

JSON doesn't support functions or undefined values:

{
  "name": "John",
  "callback": function() {},  // ERROR! Functions not allowed
  "status": undefined        // ERROR! undefined not allowed
}

4. Unquoted Property Names

All object property names must be quoted:

{
  name: "John",    // ERROR! Missing quotes around property name
  "age": 30
}

5. Invalid Number Formats

Numbers can't start with multiple zeros or use certain notations:

{
  "amount": 01.50,        // ERROR! Leading zero
  "hex": 0xFF,           // ERROR! Hex not allowed
  "scientific": 1.23e5,  // Valid scientific notation
  "infinity": Infinity   // ERROR! Infinity not allowed
}

6. Comments in JSON

JSON doesn't support comments:

{
  // This is a comment     ERROR!
  "name": "John",
  "age": 30              /* Block comment - ERROR! */
}

7. Unclosed Structures

All arrays and objects must be properly closed:

{
  "name": "John",
  "items": [
    "apple",
    "orange"    // ERROR! Missing closing bracket
  "age": 30

About viewjson.online

viewjson is an online json viewer, json beautifier, json formatter, json data converter, json diff, json validator tools.

Features

JSON Basic Process
Provide some basic json data process methods daily used, such as json minify, json prettify, json highlight.
JSON Conversion
Easily convert JSON data to and from various formats, including JSON to XML,JSON to CSV, JSON to YAML, JSON to Base64,JSON to HTML.
JSON Formatting
Keep your JSON data organized with our formatting tools that ensure readability and consistency.
JSON Validation
Provide a simple and efficient json vaildation tool to find any json data syntax errors.
JSON Diff
Use json diff tool to Compare two JSON files and identify the differences between them.
JSON Path
Use json path tool to query and extract data from JSON documents using JSONPath expressions.

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