- JSON (json.org)
- JSON Editor Online (jsoneditoronline.org)
- Convert JSON Array to Markdown Table, CSV and more (tableconvert.com)
JSON CHEAT SHEET
This is a quick reference cheat sheet for understanding and writing JSON format configuration files.
configformat
3
Sections
16
Cards
#Getting Started
Introduction
JSON is a lightweight text-based open standard designed for human-readable data interchange.
- JSON stands for JavaScript Object Notation
- JSON is easy to read and write.
- JSON is language agnostic data-interchange format
- JSON filename extension is
.json - JSON Internet Media type is
application/json
{.marker-round}
Examples
{
"name": "Jason",
"age": 39,
"height": 1.92,
"gender": "M",
"salary": 70000,
"married": true,
"children": [
{ "name": "Tom", "age": 9, "gender": "M" },
{ "name": "Ava", "age": 7, "gender": "F" }
]
}
Types
| Type | Description |
|---|---|
Number | Double precision floating-point |
String | Series of characters |
Boolean | true or false |
Array | Ordered sequence of values |
Value | String, Number, Boolean, null etc |
Object | Unordered collection of key/value pairs |
null | Null or Empty |
String
\" | Double quote |
\\ | Backslash |
\/ | Forward slash |
\b | Backspace |
\f | Form feed |
\n | Newline |
\r | Carriage return |
\t | Tab |
\u | Trailed by four hex digits |
Examples
{
"url": "https://cheatsheets.zip",
"msg": "Hi,\n\"CheatSheets.zip\"",
"intro": "Share quick reference and cheat sheet for developers."
}
Invalid String
{ "foo": "bar" }
Have to be delimited by double quotes
Number
| Type | Description |
|---|---|
Integer | Digits 1-9, 0 and positive or negative |
Fraction | Fractions like 0.3, 3.9 |
Exponent | Exponent like e, e+, e-, E, E+, E |
Examples
{
"positive": 12,
"negative": -1,
"fraction": 10.25,
"exponent": 1.0e2,
"zero": 0
}
Invalid Number
{ "foo": 0xff }
In JSON you can use only Decimal Literals
Objects
{
"color": "Purple",
"id": "210",
"composition": {
"R": 70,
"G": 39,
"B": 89
},
"empty_object": {}
}
Multiple key/value pairs separated by a comma
Arrays
[1, 2, 3, 4, 5]
Begins with [ and ends with ]
Array of objects
{
"children": [
{ "name": "Jimmy Smith", "age": 15 },
{ "name": "Sammy Sosa", "age": 12 }
]
}
Object of arrays
{
"attributes": ["a1", "a2"],
"methods": ["getter", "setter"],
"empty_array": []
}
2D Array
{
"my_sequences": [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9, 0],
[10, 11]
]
}
Object of objects
{
"Mark McGwire": {
"hr": 65,
"avg": 0.278
},
"Sammy Sosa": {
"hr": 63,
"avg": 0.288
}
}
Nested
{
"Jack": {
"id": 1,
"name": "Franc",
"salary": 25000,
"hobby": ["a", "b"],
"location": {
"country": "A",
"city": "A-A"
}
}
}
#Access JSON in JavaScript
Access Object
let myObject = {
name: 'Jason',
last: 'Doe',
age: 39,
gender: 'M',
salary: 70000,
married: true
};
myObject.name | "Jason" |
myObject["name"] | "Jason" |
myObject.age | 39 |
myObject.other | undefined |
myObject[0] | undefined |
Access Nested
let myObject = {
ref: {
name: 0,
last: 1,
age: 2,
gender: 3,
salary: 4,
married: 5
},
jdoe: ['Jason', 'Doe', 39, 'M', 70000, true],
jsmith: ['Tom', 'Smith', 42, 'F', 80000, true]
};
myObject.ref.age | 2 |
myObject["ref"]["age"] | 2 |
myObject.jdoe | "Jason", "Doe", 39 ... |
myObject.jsmith[3] | "F" |
myObject[1] | undefined |
Access Array of Objects
let myArray = [
{
name: 'Jason',
last: 'Doe',
age: 39,
gender: 'M',
salary: 70000,
married: true
},
{
name: 'Tom',
last: 'Smith',
age: 42,
gender: 'F',
salary: 80000,
married: true
},
{
name: 'Amy',
last: 'Burnquist',
age: 29,
gender: 'F',
salary: 60000,
married: false
}
];
myArray[0] | {"name": "Jason", ...} |
myArray[1].name | "Tom" |
myArray[1][2] | 42 |
myArray[3] | undefined |
myArray[3].gender | TypeError: Cannot read... |
Access Array
let myArray = ['Jason', 'Doe', 39, 'M', 70000, true];
myArray[1] | "Doe" |
myArray[5] | true |
myArray[6] | undefined |