JavaScript Function to Fetch All Pages from a Paginated API

async function fetchAllPaginatedData(baseUrl, pageSize = 10, initialPage = 1) {
  let allItems = [];
  let currentPage = initialPage;
  let hasMore = true;

  while (hasMore) {
    try {
      // Adjust URL parameters based on your API's pagination scheme
      // Common schemes: 'page' and 'per_page', 'offset' and 'limit', 'cursor'
      const url = `${baseUrl}?page=${currentPage}&per_page=${pageSize}`;
      console.log(`Fetching page ${currentPage} from ${url}`);

      const response = await fetch(url);
      if (!response.ok) {
        throw new Error(`HTTP error! Status: ${response.status}`);
      }
      const pageData = await response.json();

      // Assuming API returns an array of items directly,
      // or an object like { data: [...], meta: { next_page: ... } }
      let itemsOnPage = [];
      if (Array.isArray(pageData)) {
        itemsOnPage = pageData;
      } else if (pageData && Array.isArray(pageData.data)) {
        itemsOnPage = pageData.data;
      } else {
        // Handle other API response structures
        console.warn("Unexpected pagination response structure:", pageData);
        break; // Stop if structure is not as expected
      }

      if (itemsOnPage.length > 0) {
        allItems = allItems.concat(itemsOnPage);
        currentPage++;
      } else {
        hasMore = false; // No more items on this page
      }

      // You might need to check specific API response fields for 'hasMore'
      // e.g., if (pageData.meta && pageData.meta.next_page === null) hasMore = false;
      // or if (pageData.links && !pageData.links.next) hasMore = false;
      // For simplicity, we assume an empty page means no more data.
      if (itemsOnPage.length < pageSize && pageData.length !== undefined) { // Check for last page if API doesn't indicate
          hasMore = false;
      }


    } catch (error)
    {
      console.error("Error fetching paginated data:", error);
      hasMore = false; // Stop on error
      throw error;
    }
  }
  return allItems;
}

// Example Usage (replace with your actual paginated API endpoint)
// async function main() {
//   try {
//     // This example uses JSONPlaceholder, which does not truly paginate this way,
//     // but you can simulate it by adjusting page sizes.
//     // For a real paginated API, uncomment and test.
//     const allPosts = await fetchAllPaginatedData('https://jsonplaceholder.typicode.com/posts', 10);
//     // const allPosts = await fetchAllPaginatedData('https://api.example.com/items', 20);
//     console.log('Total items fetched:', allPosts.length);
//     // console.log('First 3 items:', allPosts.slice(0, 3));
//   } catch (error) {
//     console.error('Failed to retrieve all paginated data:', error);
//   }
// }
// main();