Generic API Response Type

type ApiResponse<T> = { success: true; data: T } | { success: false; error: string };

async function fetchApi<T>(url: string): Promise<ApiResponse<T>> {
  try {
    const response = await fetch(url);
    if (!response.ok) {
      return { success: false, error: `HTTP ${response.status}` };
    }
    const data: T = await response.json();
    return { success: true, data };
  } catch (error) {
    return { success: false, error: (error as Error).message };
  }
}

interface User {
  id: number;
  name: string;
}

const result = await fetchApi<User>('/api/user/1');

if (result.success) {
  console.log(result.data.name); // Type-safe access
} else {
  console.error(result.error);
}