JSON Cheatsheet

{
  "name": "Jason",
  "age": 39,
  "married": true,
  "children": [
    { "name": "Tom", "age": 9 },
    { "name": "Ava", "age": 7 }
  ]
}

{
  "msg": "Hi,\n\"CheatSheets.zip\"",
  "url": "https://cheatsheets.zip"
}

{ foo: "bar" } // ❌ invalid — keys must be in double quotes

{
  "positive": 12,
  "negative": -1,
  "fraction": 10.25,
  "exponent": 1.0e2,
  "zero": 0
}

{ "foo": 0xff } // ❌ Hex is invalid in JSON

{
  "color": "Purple",
  "id": "210",
  "composition": { "R": 70, "G": 39, "B": 89 }
}

[1, 2, 3, 4, 5]

{
  "children": [
    { "name": "Jimmy", "age": 15 },
    { "name": "Sammy", "age": 12 }
  ]
}

{
  "attributes": ["a1", "a2"],
  "methods": ["getter", "setter"],
  "empty": []
}

{
  "matrix": [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9, 0]
  ]
}

{
  "Mark": { "hr": 65, "avg": 0.278 },
  "Sammy": { "hr": 63, "avg": 0.288 }
}

{
  "Jack": {
    "id": 1,
    "hobby": ["a", "b"],
    "location": { "country": "A", "city": "A-A" }
  }
}

myObject.name;
myObject["name"];
myObject[0]; // undefined

myObject.ref.age;
myObject.jsmith[3];

myArray[0];
myArray[1].name;
myArray[3]; // undefined

myArray[1]; // "Doe"
myArray[5]; // true