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Practice Object Interaction

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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.

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    How was that challenge? 0:00
    We're getting pretty far into our library app. 0:02
    You just finished adding the check out and return book methods to the patron class. 0:04
    You calculated and set the due date inside the check out method. 0:08
    But there's another way this could be accomplished that I prefer. 0:12
    Consider this. 0:15
    There's a property on the book class called out, and 0:17
    it holds a Boolean value, true or false. 0:19
    The book either is or isn't checked out. 0:22
    The book has a due date property. 0:25
    These two properties are set manually in the checkout method on the patron class. 0:26
    But wouldn't it be great if when a book object is marked out, 0:32
    that it would trigger the due date to be calculated and set as well. 0:35
    And of course, when the book is marked back in, 0:38
    it would trigger the dueDate property to be changed back to null. 0:41
    That is the beauty of setter methods. 0:45
    Marking a book as out or in and calculating and setting a due date inside 0:47
    both the checkOut and return book methods is a bulky way to go about these tasks. 0:52
    If we had a setter method for the out property, we could also figure out the due 0:58
    date, and set or unset the due date property at the same time. 1:02
    Meaning our check out and return book methods would become a lot more concise. 1:06
    Let's refactor our code a little bit to try this new approach. 1:11
    Open up the attached workspace for an updated readme or 1:15
    check out the teacher's notes for the new instructions. 1:17
    The following step provides a text based explanation of what we've discussed in 1:20
    this video and might offer some more insight if you're feeling confused. 1:24
    Give the coding a try and then check out the solution before joining me again. 1:28

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