Might need to add those last few lines to the controller.ts file.
/* return the book if found and undefined if not */
const searchBookByIsbn = (isbn: string): ( IBook | undefined ) => books.filter(book => book.isbn === isbn )[0]
export { getBooks, getBook, addBook, updateBook, deleteBook }
Great article.
Might need to add those last few lines to the
controller.tsfile.Ah yes, Thank you.