Refactoring / Null Object Part Two

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This coding exercise comes from Upcase, the online learning platform we run. It's part of the Refactoring course and is just one small sample of all the great material available on Upcase, so be sure to visit and check out the rest.

Exercise Intro

In this exercise, you'll use the Null Object pattern to encapsulate conditional logic relating to nil. The conditions in this exercise are more complex than the ones in the first exercise. You may want to use more than one Null Object class.

Watch a relevant example from The Weekly Iteration.

Instructions

To start, you'll want to clone and run the setup script for the repo

git clone git@github.com:thoughtbot-upcase-exercises/null-object-part-two.git
cd null-object-part-two
bin/setup

Open lib/user.rb in your favorite editor.
Look for conditionals related to nil.
Introduce a Null Object. Think of a good name based on what nil represents in this context.
Replace a single conditional by moving the nil logic to the Null Object.
Repeat step four until nothing else can be moved to the Null Object.
Repeat steps three through five until the nil logic is entirely encapsulated within Null Objects.
Make sure all tests pass by running rake.

Featured Solution

Check out the featured solution branch to see the approach we recommend for this exercise.

Forum Discussion

If you find yourself stuck, be sure to check out the associated Upcase Forum discussion for this exercise to see what other folks have said.

Next Steps

When you've finished the exercise, head on back to the Refactoring course to find the next exercise, or explore any of the other great content on Upcase.

License

Credits

This exercise is maintained and funded by thoughtbot, inc.

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