Author detail page

The author detail page needs to display the information about the specified Author, identified using their (automatically generated) _id field value, along with a list of all the Book objects associated with that Author.


Open /controllers/authorController.js.

Add the following lines to the top of the file to require() the Book module needed by the author detail page (other modules such as "express-async-handler" should already be present).

const Book = require("../models/book");

Find the exported author_detail() controller method and replace it with the following code.

// Display detail page for a specific Author.
exports.author_detail = asyncHandler(async (req, res, next) => {
  // Get details of author and all their books (in parallel)
  const [author, allBooksByAuthor] = await Promise.all([
    Book.find({ author: }, "title summary").exec(),

  if (author === null) {
    // No results.
    const err = new Error("Author not found");
    err.status = 404;
    return next(err);

  res.render("author_detail", {
    title: "Author Detail",
    author: author,
    author_books: allBooksByAuthor,

The approach is exactly the same as described for the Genre detail page. The route controller function uses Promise.all() to query the specified Author and their associated Book instances in parallel. If no matching author is found an Error object is sent to the Express error handling middleware. If the author is found then the retrieved database information is rendered using the "author_detail" template.


Create /views/author_detail.pug and copy in the following text.

extends layout

block content

  h1 Author: #{}
  p #{author.date_of_birth} - #{author.date_of_death}


    h2(style='font-size: 1.5rem;') Books
    if author_books.length
        each book in author_books
            a(href=book.url) #{book.title}
          dd #{book.summary}
      p This author has no books.

Everything in this template has been demonstrated in previous sections.

What does it look like?

Run the application and open your browser to http://localhost:3000/. Select the All Authors link, then select one of the authors. If everything is set up correctly, your site should look something like the following screenshot.

Author Detail Page - Express Local Library site

Note: The appearance of the author lifespan dates is ugly! We'll address that in the final challenge in this article.

Next steps