Add pagination methods and tests for JsonServer class

Author: webmasterdevlin

src/lib/server.ts

@@ -134,6 +134,57 @@ export class JsonServer {
  }
  }
 
+ /**
+ * Creates pagination metadata based on request parameters
+ *
+ * @param total - Total number of items
+ * @param page - Current page number
+ * @param perPage - Items per page
+ * @returns Pagination metadata with first, prev, next, last, pages, and items
+ */
+ private createPaginationMetadata(
+ total: number,
+ page: number,
+ perPage: number
+ ): Record<string, any> {
+ const totalPages = Math.ceil(total / perPage);
+
+ return {
+ first: 1,
+ prev: page > 1 ? page - 1 : null,
+ next: page < totalPages ? page + 1 : null,
+ last: totalPages || 1,
+ pages: totalPages || 1,
+ items: total,
+ };
+ }
+
+ /**
+ * Get paginated data with metadata
+ *
+ * @param collection - Data collection to paginate
+ * @param page - Current page number (default: 1)
+ * @param perPage - Items per page (default: 10)
+ * @returns Object with pagination metadata and data
+ */
+ private getPaginatedData(
+ collection: any[],
+ page: number = 1,
+ perPage: number = 10
+ ): Record<string, any> {
+ const total = collection.length;
+ const start = (page - 1) * perPage;
+ const end = Math.min(start + perPage, total);
+ const data = collection.slice(start, end);
+
+ const paginationMeta = this.createPaginationMetadata(total, page, perPage);
+
+ return {
+ ...paginationMeta,
+ data,
+ };
+ }
+
  /**
  * Get paginated resources from a collection
  *
@@ -190,7 +241,10 @@ export class JsonServer {
  * @returns Boolean indicating if there are more pages to iterate
  */
  continueToIterate(currentPage: number, pageSize: number, totalItems: number): boolean {
- return currentPage * pageSize < totalItems;
+ // The pagination should continue if there are still more items to display
+ const startIndex = (currentPage - 1) * pageSize;
+ const endIndex = startIndex + pageSize;
+ return endIndex < totalItems;
  }
 
  /**

test/server.test.ts

@@ -79,4 +79,23 @@ describe('JsonServer', () => {
  expect(server.setIdField('_id')).toBe(server);
  });
  });
+
+ describe('pagination methods', () => {
+ it('should determine if pagination should continue', () => {
+ // Should continue - more pages available
+ expect(server.continueToIterate(1, 10, 25)).toBe(true);
+
+ // Should continue - exactly one more page
+ expect(server.continueToIterate(1, 10, 20)).toBe(true);
+
+ // Should not continue - on last page
+ expect(server.continueToIterate(2, 10, 20)).toBe(false);
+
+ // Should not continue - on last page with incomplete items
+ expect(server.continueToIterate(3, 10, 25)).toBe(false);
+
+ // Edge case - single page
+ expect(server.continueToIterate(1, 20, 15)).toBe(false);
+ });
+ });
 });