[JITERA] Add PATCH endpoint for partial updates to books

Created by: chi-jitera

Overview

This pull request introduces a new PATCH endpoint for the /books/:id route, allowing for partial updates to book documents in the database. This enhancement follows the existing structure and conventions of the codebase, ensuring consistency and maintainability.

Changes

1. Updated Routes:

   • Added a PATCH route in /routes/bookRoutes.js that maps to the patchBook method in the bookController.

   router.patch('/books/:id', bookController.patchBook); // ← PATCH endpoint

2. Controller Method:

   • Implemented the patchBook method in /controllers/bookController.js. This method calls the patchBook service logic and includes error handling that adheres to existing conventions.

   exports.patchBook = async (req, res) => {
       try {
           const book = await bookService.patchBook(req.params.id, req.body);
           res.json(book);
       } catch (error) {
           res.status(400).json({ error: error.message });
       }
   };

3. Service Logic:

   • Added the patchBook method in /services/bookService.js to handle the partial update logic. This method validates the publishedYear if present and uses findByIdAndUpdate with $set to update only the specified fields.

   exports.patchBook = async (bookId, patchData) => {
       if (patchData.publishedYear !== undefined) {
           if (patchData.publishedYear > new Date().getFullYear()) {
               throw new Error('Published year cannot be in the future.');
           }
       }
       const book = await Book.findByIdAndUpdate(
           bookId,
           { $set: patchData },
           { new: true, runValidators: true }
       );
       if (!book) throw new Error('Book not found');
       return book;
   };

Summary

• This update allows for partial updates to book records, enhancing the flexibility of the API.
• Validation is enforced on the publishedYear field to prevent future dates.
• The implementation follows existing error handling and response conventions, ensuring a seamless integration into the current codebase.

Let me know if you would like to discuss further refinements or if tests are needed for this feature.