What is an Object?

[MUSIC] 0:00 Hey everyone, I'm Guil, a developer and instructor here at Treehouse. 0:09 I'm happy that you've joined me here to continue your JavaScript learning journey. 0:13 Now, it's time to learn about JavaScript objects. 0:17 Objects are a really big subject. 0:19 In fact, JavaScript is often referred to as an object-based programming language, 0:22 which means that the language is made up of different types of objects. 0:27 You've learned that many core JavaScript features, strings, arrays, numbers, 0:30 and Boolean, for example, are either an object or can be treated as an object. 0:35 But what exactly is an object? 0:40 One of the simplest ways to think of an object is something that has properties 0:44 and methods. 0:49 A property is like a variable that belongs to the object. 0:50 And a method is something that object can do or that can be done to the object. 0:53 You've already worked with or 0:59 seen examples of objects like the built in map and console objects. 1:00 An array for example, is also an object and it has a property named length. 1:05 It also has many methods that let you do something to the array or 1:09 with the elements in the array. 1:13 For example, the push method adds an element to the end of an array. 1:15 There are even programming patterns that are object oriented, or 1:18 that specifically use objects as a flexible way of developing applications. 1:22 But that's part of more advanced JavaScript programming, 1:26 which you'll learn about in a later course. 1:29 In this course, you're going to focus on one specific use for 1:31 objects, storing and accessing related data. 1:35 You've already worked with two ways of storing data with JavaScript, 1:38 assigning a value to a variable and storing a list of values in an array. 1:42 JavaScript objects let you store data as what are called key value pairs or 1:47 property value pairs. 1:52 A key, or a property name, is like a variable name, and 1:53 a value is like the value of that variable. 1:56 In other words, 2:00 you might think of an object as the single item that holds multiple variables. 2:00 Let's look at how to create an object. 2:05 You start by assigning what's called an object literal to a variable. 2:08 The curly braces assigned to the variable name represents an object literal. 2:12 You can't do much with an empty object, so you'll usually add data inside the object. 2:17 Within the braces, you add a property name also called a key, followed by a colon and 2:21 a valid value, like a string. 2:26 Notice that in this example, the property name, or key, is not within quotes. 2:29 The key acts like a variable name. 2:33 So the rules of variable names apply to it. 2:35 Only use letters, numbers, a dollar sign, and underscore and 2:38 don't start the name with a number. 2:42 The colon separates the property name from its value. 2:44 And the value can be any of the valid JavaScript values you've learned about 2:47 a string, number, Boolean, array, or even another object. 2:51 You separate each property value pair with a comma, 2:54 similar to how you separate elements in an array with commas. 2:57 To make object literals more readable, 3:01 developers place each key value pair on its own line. 3:03 In addition, each line is indented inside the object. 3:07 This makes it easier to see that those lines belong to the object. 3:11 Now you might understand why they're called object literals. 3:15 You literally write out the object and the contents inside it in one statement. 3:18 This is compared to other built in objects like map, console, 3:22 and document, and primitive types like strings, numbers, and 3:26 Booleans, which are treated as objects behind the scenes. 3:30 Up next, you'll start creating objects, adding data inside them, 3:34 then learn how to access and manipulate that data in your program. 3:37