- When Object Literals Aren’t Enough 3:04
- Writing Your First Class 3:28
- Adding Properties Inside the Constructor Method 2:33
- Creating a new class 3 objectives
- Instantiating a Pet Object 2:32
- Instantiating an object 1 objective
- Adding Methods To Our Class 3:15
- Adding methods to classes 2 objectives
- Review Working with Classes in JavaScript 4 questions
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Instantiating a Pet Object
2:32Learn how to instantiate new objects from classes.
Now that we've finished our constructor
method, we're ready to create or
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instantiate a pet object.
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Creating an instance of a class is really
easy, and you might have seen this syntax
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before, perhaps when using the JavaScript
date object, or when creating a new array.
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First, declare a variable
that will hold your object,
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set it equal to the keyword new,
followed by the class name.
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Make sure the first letter of
the class name is capitalized,
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just like when we declared the Pet class.
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And remember, we'll want to pass in
the correct parameters, age, animal, and
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breed, to the constructor
method inside the class.
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In this example,
those values will be dog, 1, and pug.
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Take a moment to practice creating
some other instances of the Pet class.
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You can use the remaining object literals,
or
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you can feel free to
model Pets of your own.
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I'm going to show this process again using
one of the other Pets from the object
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literal examples.
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So I will do const vera = new Pet, and
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then I'll pass in
the parameters which are dog,
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8 for her age, and then border collie,
which is her breed.
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Great, now let's write a line to
output the ernie object, save,
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and then hop down to the console to
run the file and see what we find.
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I'll make the console area a little larger
so we have some more room to work with.
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To run the file, we're going to use node.
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Your workspace is all set up to use node,
so running the file is simple.
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If you're not using workspaces,
check the teacher's notes for
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some information on how to install
node on your local machine.
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In the console, type the word node
followed by the name of the file.
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Which, if you've been following along,
is Pet.js, and then hit Enter.
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Your output will appear in the console.
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You should be able to see
all of the properties and
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their values attached to the ernie object.
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As you can see here,
we have animal, age, and breed.
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What do you see in your console,
does it match with what you see here?
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If you got an error, go back and
follow along with this video again.
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You can also post about anything you're
struggling with to the Treehouse
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community.
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Not only will this help you
get the answers you need, but
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it will help other students who
might be having similar struggles.
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A huge part of working as a developer is
knowing how to find answers online and
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helping others when you can.
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No developer knows everything,
and that's why we work together.
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