feat: add calculation methods

react-typescript/src/App.tsx

@@ -4,12 +4,12 @@ import Item from './Item';
 function App() {
   return (
     <div className="App">
-      <Item name="+5 Dexterity Vest" sellIn={10} quality={20} isConjured={true} />
+      <Item name="+5 Dexterity Vest" sellIn={10} quality={20} isConjured={false} />
       <Item name="Aged Brie" sellIn={2} quality={0} isConjured={false} />
       <Item name="Elixir of the Mongoose" sellIn={5} quality={7} isConjured={false} />
-      <Item name="Sulfuras, Hand of Ragnaros" sellIn={0} quality={80} isConjured={false} />
+      <Item name="Sulfuras, Hand of Ragnaros" sellIn={1} quality={80} isConjured={false} />
       <Item name="Backstage passes to a TAFKAL80ETC concert" sellIn={15} quality={20} isConjured={false} />
-      <Item name="Conjured Mana Cake" sellIn={3} quality={6} isConjured={false} />
+      <Item name="Conjured Mana Cake" sellIn={3} quality={6} isConjured={true} />
     </div>
   );
 }

react-typescript/src/Item.tsx

@@ -1,22 +1,60 @@
 import { useEffect, useState } from "react";
 
-function calculateQuality(quality: number, isConjured: boolean): number {
-  const calculatedQuality = quality;
-  const calculatedBias = isConjured ? 2 : 1;
+function calculateQuality(name:string, quality: number, sellIn: number,isConjured: boolean): number {
+  const sellInAmount = sellIn;
 
-  if(calculatedQuality > 50) {
+  let calculatedQuality = quality;
+  let degradeRate = 1;
+  let qualityIdentifier = 1;
+
+  if(sellInAmount <= 0) {
+    return calculatedQuality;
+  }
+
+  if(name.includes("Sulfuras")) {
+    return 80;
+  };
+
+  if(calculatedQuality >= 50) {
     return 50;
-  } else if(calculatedQuality < 0) {
+  } else if(calculatedQuality <= 0) {
     return 0;
   }
 
-  
+  if(isConjured) {
+    degradeRate = 2;
+  }
 
-  return calculatedQuality * calculatedBias;  
+  if(name.includes('Aged Brie')) {
+    qualityIdentifier = -1;
+  }
+
+  if(name.includes('Backstage passes')) {
+    if(sellInAmount <= 10 && sellInAmount > 5) {
+      qualityIdentifier = -3;
+    } else if(sellInAmount <= 5 && sellInAmount > 0) {
+      qualityIdentifier = -2;
+    } else if(sellInAmount <= 0) {
+      qualityIdentifier = 0;
+      degradeRate = 0;
+    }
+  }
+
+  return degradeRate * calculatedQuality - qualityIdentifier;  
 };
 
-function calculateSellIn(sellIn: number): number {
-    return sellIn - 1;
+function calculateSellIn(name:string, sellIn: number): number {
+  let sellInAmount = sellIn;
+
+  if(name.includes("Sulfuras")) {
+    return sellInAmount;
+  };
+
+  if(sellInAmount <= 0) {
+    return 0;
+  }
+
+  return sellIn - 1;
 };
 
 type ItemProps = {
@@ -49,17 +87,17 @@ const Item = (props: ItemProps) => {
 
     return (
         <div>
-          <p color={isConjured ? 'Red' : 'Green'}>The name {name}</p>
+          <p color={isConjured ? 'Red' : 'Green'}>{name}</p>
 
-          <p>The quality {quality}</p>
+          <p>{quality}</p>
 
-          <p>The sellIn {sellIn}</p>
+          <p>{sellIn}</p>
           <br></br>
           <button onClick={() => { 
-            setSellIn(calculateSellIn(sellIn));
-            setQuality(calculateQuality(quality, isConjured));
+            setQuality(calculateQuality(name, sellIn, quality, isConjured));
+            setSellIn(calculateSellIn(name, sellIn));
             }}>
-            Next Day
+            Purchase
           </button>
           <br></br>
         </div>