JSON Data Types
In JSON, values must be one of the following data types:
- a string
- a number
- an object (JSON object)
- an array
- a boolean
- null
JSON values cannot be one of the following data types:
- a function
- a date
- undefined
JSON Strings
Strings in JSON must be written in double quotes.
Example
{ “name”:“John” }
JSON Numbers
Numbers in JSON must be an integer or a floating point.
Example
{ “age”:30 }
JSON Objects
Values in JSON can be objects.
Example
{
“employee”:{ “name”:“John”, “age”:30, “city”:“New York” }
}
Objects as values in JSON must follow the same rules as JSON objects.
JSON Arrays
Values in JSON can be arrays.
Example
{
“employees”:[ “John”, “Anna”, “Peter” ]
}
JSON Booleans
Values in JSON can be true/false.
Example
{ “sale”:true }
JSON null
Values in JSON can be null.
Example
{ “middlename”:null }
JSON Objects
Object Syntax
Example
{ “name”:“John”, “age”:30, “car”:null }
JSON objects are surrounded by curly braces {}.
JSON objects are written in key/value pairs.
Keys must be strings, and values must be a valid JSON data type (string, number, object, array, boolean or null).
Keys and values are separated by a colon.
Each key/value pair is separated by a comma.
Accessing Object Values
You can access the object values by using dot (.) notation:
Example
myObj = { “name”:“John”, “age”:30, “car”:null };
x = myObj.name;
You can also access the object values by using bracket ([]) notation:
Example
myObj = { “name”:“John”, “age”:30, “car”:null };
x = myObj[“name”];