Data Types
number |
var myNum = 123.456; |
Series of numbers; decimals ok; double-precision floating-point format |
string |
var myString = "abcdef"; |
Series of characters (letters, numbers, or symbols); double-quoted UTF-8 with backslash escaping |
boolean |
var myBool = true; |
true or false |
array |
var myArray = [ "a", "b", "c", "d" ]; |
sequence of comma-separated values (any data type); enclosed in square brackets |
object |
var myObject = { "id": 7 }; |
unordered collection of comma-separated key/value pairs; enclosed in curly braces; properties (keys) are distinct strings |
null |
var myNull = null; |
variable with null (empty) value |
undefined |
var myUndefined; |
variable with no value assigne |
|
|
Objects
var myObject = {
"first": "John",
"last": "Doe",
"age": 39,
"sex": "male",
"salary": 70000,
"registered": true
};
|
Access object properties
myObject.sex |
returns "male" |
myObject["age"] |
returns 39 |
myObject[0] |
returns "John" |
myObject.something |
returns undefined |
myObject[6] |
returns undefined |
Array of objects
var myArray = [
{
"first": "John",
"last": "Doe",
"age": 39,
"sex": "male",
"salary": 70000,
"registered": true
},
{
"first": "Jane",
"last": "Smith",
"age": 42,
"sex": "female",
"salary": 80000,
"registered": true
},
{
"first": "Amy",
"last": "Burnquist",
"age": 29,
"sex": "female",
"salary": 60000,
"registered": false
}
];
|
Access array elements
myArray[0] |
returns { "fist": "John", "last": "Doe" ... } |
myArray[1] |
returns { "fist": "Jane", "last": "Smith" ... } |
myArray[1].first |
returns "Jane" |
myArray[1][2] |
returns 42 |
myArray[2].registered |
returns false |
myArray[3] |
returns undefined |
myArray[3].sex |
error: "cannot read property..." |
|
|
Arrays
var myArray = [
"John",
"Doe",
39,
"M",
70000,
true
];
|
Access array elements
myArray[1] |
returns "Doe" |
myArray[5] |
returns true |
myArray[6] |
returns undefined |
Nested objects and arrays
var myObject = {
"ref": {
"first": 0,
"last": 1,
"age": 2,
"sex": 3,
"salary": 4,
"registered": 5
},
"jdoe1": [
"John",
"Doe",
39,
"male",
70000,
true
],
"jsmith1": [
"Jane",
"Smith",
42,
"female",
80000,
true
]
};
|
Access nested elements
myObject.ref.first |
returns 0 |
myObject.jdoe1 |
returns [ "John", "Doe", 39 ... ] |
myObject[2] |
returns [ "Jane", "Smith", 42 ... ] |
myObject.jsmith1[3] |
returns "female" |
myObject[1][5] |
returns true |
myObject.jdoe1[myObject.ref.last] |
returns "Doe" |
myObject.jsmith1[myObject.ref.age] |
returns 42 |
|
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Comments
Great reference, very handy!
You carried over some typos from https://www.json.com/cheat-sheet-v-1-3
You might correct "fist" to "first" in a few places.
I having some difficulty downloading the JSON cheatsheet I probably need to Add a Comment.
Still having difficulty download loading PDF of JSON Cheatsheet.
Great cheatsheet.
Add a Comment
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