JSON DataTypes

Below given data types are supported by JSON:

JSON values must not be one of the below-given data types:

• a function
• a date
• undefined

Number

• It is a double-precision floating-point layout in JavaScript and it relies upon implementation.
• Octal and hexadecimal formats aren't used.
• No NaN or Infinity is utilized in Number.

The following table indicates the number types−

Syntax

var json-object-name = { string : number_value, .......}

Example

Example representing the Number Datatype, the value must not be quoted:

var obj = {marks: 97}

String

• It is a series of 0 or greater double-quoted Unicode characters with backslash escaping.
• Character is a single character string i.e. a string with length 1.

The table indicates numerous unique characters that you may use in strings of a JSON document:

Syntax

var json-object-name = { string : "string value", .......}

Example

String Datatype Example is given below:

var obj = {name: 'Amit'}

Boolean

It comprises two and more values.

Syntax

var json-object-name = { string : true/false, .......}

Example

var obj = {name: 'Amit', marks: 97, distinction: true}

Array

• It is an ordered series of values.
• These are enclosed in square brackets which means that the array starts with.[. and ends with .].
• The values are separated by, (comma).
• Array indexing may begin out at zero or 1.
• Arrays need to be used when the key names are sequential integers.

Syntax

[ value, .......]

Example

In the below given example it represents an array containing multiple objects:

{
   "books": [
      { "language":"Java" , "edition":"second" },
      { "language":"C++" , "lastName":"fifth" },
      { "language":"C" , "lastName":"third" }
   ]
}

Object

• It is an unordered set of name/value pairs.
• Objects are enclosed in curly braces, that is, it starts with ''.
• Each name is accompanied by ':'(colon) and the key/value pairs are separated by, (comma).
• The keys need to be strings and must be distinct from each other.
• Objects have to be used when the key names are arbitrary strings.

Syntax

{ string : value, .......}

Example

Example showing object

{
   "id": "011A",
   "language": "JAVA",
   "price": 500,
}

WhiteSpace

It may be inserted between any pair of tokens. It can be added to make a code more readable. The example indicates statement with and without whitespace −

Syntax

{string:" ",....}

Example

var obj1 = {"name": "Sachin Tendulkar"}
var obj2 = {"name": "SauravGanguly"}

Null

It simply means an empty type

Syntax

null

Example

var i = null;
if(i == 1) {
   document.write("<h1>value is 1</h1>");
} else {
   document.write("<h1>value is null</h1>");
}

JSON Value

It consists of −

• number (integer or floating-point)
• string
• boolean
• array
• object
• null

Syntax

String ' Number ' Object ' Array ' TRUE ' FALSE ' NULL

Example

var i = 1;

var j = "Sachin";

var k = null;