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Explanation: A Better Way With Setters Methods

1:32 with Ashley Boucher

We've written the `checkOut()` and `returnBook()` methods, but we have an opportunity to take advantage of JavaScript's "setter" methods and should refactor our code.

Instructions for Workspace

Your instructions are as follows:

1) Change the out property initialization in the Book class constructor method to _out.

2) Add a setter method called out() to the Book class. It should receive one argument, a boolean value.

  • Inside the setter method, set the value of the _out backing property to the parameter.

  • Then, inside the setter method, check the value of the _out backing property. If it's true, calculate the due date and set the Book object's dueDate property. If it's false, set the dueDate property to null.

3) Add a getter method to the Book class called out(). It should return the value of the _out backing property.

4) Back in the Patron class, refactor your checkOut() method to use the new out() setter method instead of your existing code.

  • 0:00

    How was that challenge?

  • 0:02

    We're getting pretty far into our library app.

  • 0:04

    You just finished adding the check out and return book methods to the patron class.

  • 0:08

    You calculated and set the due date inside the check out method.

  • 0:12

    But there's another way this could be accomplished that I prefer.

  • 0:15

    Consider this.

  • 0:17

    There's a property on the book class called out, and

  • 0:19

    it holds a Boolean value, true or false.

  • 0:22

    The book either is or isn't checked out.

  • 0:25

    The book has a due date property.

  • 0:26

    These two properties are set manually in the checkout method on the patron class.

  • 0:32

    But wouldn't it be great if when a book object is marked out,

  • 0:35

    that it would trigger the due date to be calculated and set as well.

  • 0:38

    And of course, when the book is marked back in,

  • 0:41

    it would trigger the dueDate property to be changed back to null.

  • 0:45

    That is the beauty of setter methods.

  • 0:47

    Marking a book as out or in and calculating and setting a due date inside

  • 0:52

    both the checkOut and return book methods is a bulky way to go about these tasks.

  • 0:58

    If we had a setter method for the out property, we could also figure out the due

  • 1:02

    date, and set or unset the due date property at the same time.

  • 1:06

    Meaning our check out and return book methods would become a lot more concise.

  • 1:11

    Let's refactor our code a little bit to try this new approach.

  • 1:15

    Open up the attached workspace for an updated readme or

  • 1:17

    check out the teacher's notes for the new instructions.

  • 1:20

    The following step provides a text based explanation of what we've discussed in

  • 1:24

    this video and might offer some more insight if you're feeling confused.

  • 1:28

    Give the coding a try and then check out the solution before joining me again.

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