Introduction to JavaScript Object Constructors. On the screen, I have a user object. If I wanted another object with the same properties, I would have to write out another object literal to do so. As a developer, I want to be able to create multiple instances of an object that maintains the same properties for each instance of that object. You can think of an object constructor as an object blueprint. I will begin by commenting out the user object and constructors are created with functions.

So, I will type function User, and User is capitalize. So, I will type function User, and User is capitalize. And now, two parameters for each object property that I wish to use. In this case, userName and email. Now, inside of the function, I'm gonna type this.userName = userName. I'm gonna type this.userName = userName. Next, I will type this.email = email. Next, I will type this.email = email.

Now, inside of this function, I'm not writing out an object, I am writing out declarative statements that will be used to create an instance of an object. This completes the user object constructor. So now, I will create a single instance of the user object, So now, I will create a single instance of the user object, const userOne = new User, don't forget the capital letter const userOne = new User, don't forget the capital letter, and this is a function so I need to pass in my arguments, stacylacey for the username and slacey@example.com stacylacey for the username and slacey@example.com for the email address. And now, I'm gonna console.log . I will execute the code. And in the console, there is an instance of the user object with the email and username properties.

So, how does the constructor function work? The new keyword is used to create a new instance of the user object, finding the keyword this to this instance of the object, creating the property of username with the value of stacylacey and email with the value of slacey@example.com. and email with the value of slacey@example.com.

So where does reusability come into play? I'm gonna make another user, const userTwo = new User, I'm gonna make another user, const userTwo = new User, passing in the username of tracylacey and a email address of tlacey@example.com. and a email address of tlacey@example.com. I will now console.log and execute the console logs. And now, in the console, there are two instances of the user object. Both of them with their own set of properties and corresponding values. And that's it. Thanks for watching at Cloud Academy.