100 algos in 100 days (Day 10-13)

Cheating a bit ... and not technically an algo.

I tried the gilded rose refactoring kata again. If you want to have a go here is a repo with a starter pack in all different languages:
https://github.com/emilybache/GildedRose-Refactoring-Kata

The below is where I got to (with a pleasing amount of test coverage):

export class Item {
  name: string;
  sellIn: number;
  quality: number;
  constructor(name: string, sellIn: number, quality: number) {
    this.name = name;
    this.sellIn = sellIn;
    this.quality = quality;
  }
}

export class Shop {
  items: Item[];
  constructor(items = []) {
    this.items = items;
  }

  updateQuality() {
    for (let i = 0; i < this.items.length; i++) {
      const currentItem = this.items[i];

      if (currentItem.name === 'Sulfuras, Hand of Ragnaros') {
        continue;
      }

      if (currentItem.quality >= 50) {
        currentItem.sellIn = currentItem.sellIn - 1;
        continue;
      }

      if (
        currentItem.name != 'Aged Brie' &&
        currentItem.name != 'Backstage passes to a TAFKAL80ETC concert'
      ) {
        //handle depreciating quality
        if (currentItem.quality > 0) {
          currentItem.quality = currentItem.quality - 1;
        }
      } else {
        //handle increasing quality
        currentItem.quality = currentItem.quality + 1;
        if (currentItem.name == 'Backstage passes to a TAFKAL80ETC concert') {
          this.handlePasses(currentItem);
        }
      }

      currentItem.sellIn = currentItem.sellIn - 1;

      //handle expired stuff
      if (currentItem.sellIn < 0) {
        if (currentItem.name === 'Aged Brie') {
          currentItem.quality = currentItem.quality + 1;
          return this.items;
        }

        if (currentItem.name === 'Backstage passes to a TAFKAL80ETC concert') {
          currentItem.quality = currentItem.quality - currentItem.quality;
          return this.items;
        }
        // check with first code if flipping them helped??! or has it changed how this works?
        if (currentItem.quality > 0) {
          currentItem.quality = currentItem.quality - 1;
        }
      }
    }

    return this.items;
  }

  private handlePasses(pass: Item) {
    if (pass.sellIn < 11) {
      pass.quality = pass.quality + 1;
    }
    if (pass.sellIn < 6) {
      pass.quality = pass.quality + 1;
    }
  }
}

Struggling a bit with this challenge over the weekend!