Objects

Object

var hero = {
  breed: "Turtle",
  occupation: "Ninja",
  'finger count':  3
};

hero.occupation; // "Ninja" - dot notation

hero["breed"]; // "Turtle" - square bracket notation

hero["finger count"]; // 3

var key = "occupation";
hero[key]; // "Ninja"

hero.height; // "undefined"

hero.name = "Michelangelo";
hero.name; // "Michelangelo"

hero["height"] = 1.5;
hero.height; // 1.5

var key = "occupation";
hero[key] = "Pizza eater";
hero.occupation; // "Pizza eater"

var original = { howmany: 1 };
var copy = original;
copy.howmany; // 1
copy.howmany = 100;
original.howmany; // 100

When you compare objects,
you'll get true only if you compare
two references to the same object.

var fido  = {breed: 'dog'};
var benji = {breed: 'dog'};

benji === fido // false

var mydog = benji;
mydog === benji // true
mydog === fido  // false