GildedRose-Refactoring-Kata

gilded-rose.ts

export class Item {
  name: string;
  sellIn: number;
  quality: number;

  constructor(name, sellIn, quality) {
    this.name = name;
    this.sellIn = sellIn;
    this.quality = quality;
  }
}

export class GildedRose {
  items: Array<Item>;

  constructor(items = [] as Array<Item>) {
    this.items = items;
  }

  updateQuality() {
    for (let i = 0; i < this.items.length; i++) {
      this.items[i].sellIn += this.sellInDelta(this.items[i]);
      this.items[i].quality = this.newQuality(this.items[i].quality, this.qualityDelta(this.items[i]));
    }

    return this.items;
  }

  sellInDelta(item: Item) { return item.name === 'Sulfuras, Hand of Ragnaros' ? 0 : -1 }

  qualityDelta(item: Item) {
    if (item.name === 'Sulfuras, Hand of Ragnaros') return 0
    if (item.name === 'Aged Brie') return item.sellIn < 0 ? 2 : 1
    if (item.name === 'Backstage passes to a TAFKAL80ETC concert') {
      if (item.sellIn < 0) return -item.quality
      if (item.sellIn < 5) return 3
      if (item.sellIn < 10) return 2
      return 1
    }
    return -(item.sellIn < 0 ? 2 : 1) * (item.name === 'Conjured Mana Cake' ? 2 : 1)
  }

  newQuality(quality: number, delta: number) { return delta > 0 ? Math.min(quality + delta, 50) : Math.max(quality + delta, 0) }
}

my forked repo with commits: https://github.com/monlovesmango/GildedRose-Refactoring-Kata