The Gilded Rose

Hi and welcome to team Gilded Rose.

As you know, we are a small inn with a prime location in a prominent city ran by a friendly innkeeper named Allison. We also buy and sell only the finest goods. Unfortunately, our goods are constantly degrading in quality as they approach their sell by date.

We have a system in place that updates our inventory for us. It was developed by a no-nonsense type named Leeroy, who has moved on to new adventures. Your task is to add the new feature to our system so that we can begin selling a new category of items.

First an introduction to our system:

• All items have a sellIn value which denotes the number of days we have to sell the item

• All items have a quality value which denotes how valuable the item is

• At the end of each day our system lowers both values for every item

Pretty simple, right? Well this is where it gets interesting:

• Once the sellIn days is less then zero, quality degrades twice as fast

• The quality of an item is never negative

• "Aged Brie" actually increases in quality the older it gets

• The quality of an item is never more than 50

• "Sulfuras", being a legendary item, never has to be sold nor does it decrease in quality

• "Backstage passes", like aged brie, increases in quality as it's sellIn value decreases; quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less but quality drops to 0 after the concert

We have recently signed a supplier of conjured items. This requires an update to our system:

• "Conjured" items degrade in quality twice as fast as normal items

Feel free to make any changes to the updateQuality method and add any new code as long as everything still works correctly. However, do not alter the Item class or items property as those belong to the goblin in the corner who will insta-rage and one-shot you as he doesn't believe in shared code ownership.

Just for clarification, an item can never have its quality increase above 50, however "Sulfuras" is a legendary item and as such its quality is 80 and it never alters.

Instructions

Consider this an exercise in refactoring a legacy system to make your feature easier to implement, and leave things in a more maintainable state than you found them in.

As with most legacy systems, we can't count on this one to fully follow the spec, and we should consider the possibility that it contains bugs that other systems compensate for and therefore depend on. Even though this example is small, let's pretend it's a legitimate legacy system that would be impractical to rewrite.

To complete the exercise, perform a gradual, step by step refactoring, showing your work with micro-commits at each step. Implement "Conjured" items when the code has improved enough to make it easy and clear. Aside from the point at which you implement the "Conjured" items spec, preserve all existing legacy behavior at each step/commit.

You'll need to initialize a new git repository to start:

git init
git add -A
git commit -m "Initial commit"

And you can package up a bundle of your completed work with:

git bundle create your_name.bundle master

Local Development

This project was bootstrapped with TSDX.

Below is a list of commands you will probably find useful.

yarn start

Runs the project in development/watch mode. Your project will be rebuilt upon changes. TSDX has a special logger for you convenience. Error messages are pretty printed and formatted for compatibility VS Code's Problems tab. Your library will be rebuilt if you make edits.

yarn build

Bundles the package to the dist folder. The package is optimized and bundled with Rollup into multiple formats (CommonJS, UMD, and ES Module).

yarn test

Runs the test watcher (Jest) in an interactive mode. By default, runs tests related to files changed since the last commit.