Objects

Objects in JavaScript

Objects is one of JavaScript's data types and used to store key & value pairs and more complex values. There are a couple of ways to create Objects. One of them is using the object literal syntax. We can put some properties in to the {...} as "key: value" pairs.

// Object literal syntax
let myCar = {
  make: "Honda",
  model: "Civic",
  yearReleased: 2014,
  hasSunroof: false,
}

Another possible way to create an object is by object constructor with the new keyword.

// Object constructor syntax
let myCar = new Object()
myCar.make = "Honda"
myCar.model = "Civic"
myCar.yearReleased = 2014
myCar.hasSunroof = false

To remove a property, we can use delete operator.

delete myCar.model;

If you want to use multiple words in key to name a property, they have to be wrapped in quotes.

let myCar = {
  make: "Honda",
  model: "Civic",
  "year released": 2014,
  hasSunroof: false,
}

In order to access the property with multiple words, dot notation would not work. However, square bracket notation has come to the rescue.

myCar.year released
// Uncaught SyntaxError: Unexpected identifier

myCar["year released"]
// output --> 2014

Computed properties

What if you want to wait for a user input to be assigned as key. You can use square bracket for computed properties.

let car = prompt("What is your favorite car?")

let garage = {
  [car] : "Awesome",
};

alert(garage.Tesla)