Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Ruby Ruby Modules Store Inventory Using Modules Extend and Include

Mateusz Leśniak
Mateusz Leśniak
4,762 Points

Creating instances array

Hi, at which point we are creating @instances array? We made a method inside Inventoryable module to conditionally assign empty array to @instances variable, but we are not calling this method. It is enough to push something inside instances and the array is created at the same time?

Christopher Phillips
Christopher Phillips
10,061 Points

Hi Mateusz,

The array is created here. Read it as "We create the instances array and it is given no value the first time it is accessed."

def instances
    @instances ||= []
end

We populated the instances array via the create method within the ClassMethods module:

def create(attributes)
    object = new(attributes)
    instances.push(object)
    return object
end

The create method is called via this code:

shirt1 = Shirt.create(name: "mtf", size: "L")