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[MUSIC]

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Hey everyone, I'm Guil, a developer and
instructor here at Treehouse.

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I'm happy that you've joined me here to
continue your JavaScript learning journey.

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Now, it's time to learn
about JavaScript objects.

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Objects are a really big subject.

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In fact, JavaScript is often referred to
as an object-based programming language,

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which means that the language is made
up of different types of objects.

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You've learned that many core JavaScript
features, strings, arrays, numbers,

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and Boolean, for example, are either
an object or can be treated as an object.

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But what exactly is an object?

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One of the simplest ways to think of
an object is something that has properties

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and methods.

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A property is like a variable
that belongs to the object.

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And a method is something that object can
do or that can be done to the object.

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You've already worked with or

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seen examples of objects like
the built in math and console objects.

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An array for example, is also an object
and it has a property named length.

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It also has many methods that let
you do something to the array or

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with the elements in the array.

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For example, the push method adds
an element to the end of an array.

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There are even programming patterns
that are object oriented, or

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that specifically use objects as
a flexible way of developing applications.

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But that's part of more advanced
JavaScript programming,

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which you'll learn about
in a later course.

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In this course, you're going to
focus on one specific use for

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objects, storing and
accessing related data.

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You've already worked with two ways
of storing data with JavaScript,

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assigning a value to a variable and
storing a list of values in an array.

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JavaScript objects let you store data
as what are called key value pairs or

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property value pairs.

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A key, or a property name,
is like a variable name, and

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a value is like the value
of that variable.

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In other words,

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you might think of an object as the single
item that holds multiple variables.

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Let's look at how to create an object.

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You start by assigning what's called
an object literal to a variable.

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The curly braces assigned to the variable
name represents an object literal.

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You can't do much with an empty object, so
you'll usually add data inside the object.

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Within the braces, you add a property name
also called a key, followed by a colon and

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a valid value, like a string.

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Notice that in this example, the property
name, or key, is not within quotes.

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The key acts like a variable name.

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So the rules of variable
names apply to it.

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Only use letters, numbers,
a dollar sign, and underscore and

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don't start the name with a number.

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The colon separates the property
name from its value.

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And the value can be any of the valid
JavaScript values you've learned about

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a string, number, Boolean,
array, or even another object.

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You separate each property
value pair with a comma,

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similar to how you separate
elements in an array with commas.

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To make object literals more readable,

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developers place each key
value pair on its own line.

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In addition,
each line is indented inside the object.

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This makes it easier to see that
those lines belong to the object.

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Now you might understand why
they're called object literals.

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You literally write out the object and
the contents inside it in one statement.

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This is compared to other built
in objects like math, console,

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and document, and
primitive types like strings, numbers, and

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Booleans, which are treated
as objects behind the scenes.

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Up next, you'll start creating objects,
adding data inside them,

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then learn how to access and
manipulate that data in your program.