Update App State Based on Events

src/components/App.js

@@ -1,18 +1,21 @@
-import React from "react";
+import React, {useState} from "react";
 import ShoppingList from "./ShoppingList";
 import itemData from "../data/items";
 
 function App() {
+  const [isDark, setIsDark] = useState(false)
 
-  // replace 'false' with a state variable that can be toggled between true and false
-  // this will be used for the Dark Mode Toggle feature
-  const appClass = false ? "App dark" : "App light"
+  function handleDarkMode() {
+    setIsDark((isDark) => !isDark)
+  }
+
+  const appClass = isDark ? "App dark" : "App light"
 
   return (
     <div className={appClass}>
       <header>
         <h2>Shopster</h2>
-        <button>Dark Mode</button>
+        <button onClick={handleDarkMode}>{isDark ? "Dark Mode" : "Light Mode" }</button>
       </header>
       <ShoppingList items={itemData} />
     </div>

src/components/Item.js

@@ -1,11 +1,19 @@
-import React from "react";
+import React, {useState} from "react";
 
 function Item({ name, category }) {
+  const [inCart, setInCart] = useState(true)
+
+  function handleCartAdd(){
+    setInCart((inCart) => !inCart)
+  }
+
+  const liClass = inCart ? "" : "in-cart"
+
   return (
-    <li className="">
+    <li className={liClass}>
       <span>{name}</span>
       <span className="category">{category}</span>
-      <button className="add">Add to Cart</button>
+      <button onClick={handleCartAdd} className="add">{inCart ? "Add to Cart" : "Remove From Cart"}</button>
     </li>
   );
 }

src/components/ShoppingList.js

@@ -1,19 +1,33 @@
-import React from "react";
+import React, {useState} from "react";
 import Item from "./Item";
 
 function ShoppingList({ items }) {
+  const [selectedCategory, setSelectedCategory] = useState("All")
+
+  function handleFilterChange(event) {
+    setSelectedCategory(event.target.value)
+  }
+
+  const itemsToDisplay = items.filter((item) => {
+    if (selectedCategory === "All") {
+      return true
+    } else {
+      return item.category === selectedCategory
+    }
+  })
+
   return (
     <div className="ShoppingList">
       <div className="Filter">
-        <select name="filter">
+        <select name="filter" onChange={handleFilterChange}>
           <option value="All">Filter by category</option>
           <option value="Produce">Produce</option>
           <option value="Dairy">Dairy</option>
           <option value="Dessert">Dessert</option>
         </select>
       </div>
       <ul className="Items">
-        {items.map((item) => (
+        {itemsToDisplay.map((item) => (
           <Item key={item.id} name={item.name} category={item.category} />
         ))}
       </ul>