solution

src/07-funktionsprogrammierung/KATA/solution.ts

@@ -0,0 +1,101 @@
+// Funktionsprogrammierung in TypeScript - Kata Lösung
+
+interface Entity {
+  id: number;
+}
+
+interface User extends Entity {
+  firstName: string;
+  age: number;
+  gender: 'male' | 'female';
+  role: 'admin' | 'moderator' | 'user';
+}
+
+interface Product extends Entity {
+  title: string;
+  price: number;
+}
+
+const fetchData = async <T extends Entity>(
+  apiUrl: string,
+  key: string
+): Promise<T[]> => {
+  try {
+    const response = await fetch(apiUrl);
+    if (!response.ok) throw new Error('Fehler beim Abrufen der Daten');
+    const data = await response.json();
+    return data[key] || [];
+  } catch (error) {
+    console.error('API Fehler:', error);
+    return [];
+  }
+};
+
+class Store<T extends Entity> {
+  private dataMap: Record<number, T> = {};
+
+  save(data: T[]): void {
+    this.dataMap = data.reduce((acc, item) => {
+      acc[item.id] = item;
+      return acc;
+    }, {} as Record<number, T>);
+  }
+
+  filterBy(predicate: (item: T) => boolean): T[] {
+    return Object.values(this.dataMap).filter(predicate);
+  }
+}
+
+const createDataStore = <T extends Entity>() => {
+  let dataMap: Record<number, T> = {};
+
+  const save = (data: T[]): void => {
+    dataMap = data.reduce((acc, item) => {
+      acc[item.id] = item;
+      return acc;
+    }, {} as Record<number, T>);
+  };
+
+  const filterBy = (predicate: (item: T) => boolean): T[] => {
+    return Object.values(dataMap).filter(predicate);
+  };
+
+  return { save, filterBy };
+};
+
+(async () => {
+  const usersStore = new Store<User>();
+  const productsStore = new Store<Product>();
+
+  // const usersStore = createDataStore<User>();
+  // const productsStore = createDataStore<Product>();
+
+  const users = await fetchData<User>('https://dummyjson.com/users', 'users');
+  usersStore.save(users);
+
+  const products = await fetchData<Product>(
+    'https://dummyjson.com/products',
+    'products'
+  );
+  productsStore.save(products);
+
+  const mapUser = (user: User) => ({ name: user.firstName, role: user.role });
+
+  console.log(
+    'Administratoren:',
+    usersStore.filterBy((user) => user.role === 'admin').map(mapUser)
+  );
+  console.log(
+    'Moderatoren:',
+    usersStore.filterBy((user) => user.role === 'moderator').map(mapUser)
+  );
+  console.log(
+    'Normale Benutzer:',
+    usersStore.filterBy((user) => user.role === 'user').map(mapUser)
+  );
+
+  //   console.log(
+  //   'Günstige Produkte:',
+  //   productsStore.filterBy((product) => product.price < 50)
+  // );
+})();