NodepubLite

This repository is a fork of kcartlidge/nodepub that is aimed to create a browser version of this awesome package.

About NodepubLite

NodepubLite is a Node module which can be used to create EPUB 3 documents.

• Files pass the IDPF online validator
• Files meet Sigil's preflight checks
• Files open fine in iBooks, Adobe Digital Editions, and Calibre
• Files open fine with the Kobo H20 ereader
• Files are fine as KindleGen input
• PNG/JPG cover images - recommend 600x800, 600x900, or similar as minimum
• Custom CSS can be provided
• Inline images within the EPUB
• Optionally generate your own contents page
• Front matter before the contents page
• Exclude sections from auto contents page and metadata-based navigation
• OEBPF and other 'expected' subfolders within the EPUB
• Support for Most Used Right To Left Languages with page-progression-direction='rtl'

Installing NodepubLite

It's on npm at https://www.npmjs.com/package/nodepub-lite. Add it as with any other module:

npm i nodepub-lite

Then import it for use:

const NodepubLite = require("nodepub-lite");

Defining your EPUB

• Documents consist of metadata and sections
  • Metadata is an object with various properties detailing the book
  • Sections are chunks of HTML that can be thought of as chapters

Here's some sample metadata:

var metadata = {
  id: "278-123456789",
  cover: {
    name: "cover.png",
    data: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=", // Blob or DataURI
  },
  title: "Unnamed Document",
  series: "My Series",
  sequence: 1,
  author: "KA Cartlidge",
  fileAs: "Cartlidge,KA",
  genre: "Non-Fiction",
  tags: "Sample,Example,Test",
  copyright: "Anonymous, 1980",
  publisher: "My Fake Publisher",
  published: "2000-12-31",
  language: "en",
  description: "A test book.",
  showContents: false,
  contents: "Table of Contents",
  source: "http://www.kcartlidge.com",
  images: [
    {
      name: "image-1.png",
      data: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=", // Blob or DataURI
    },
  ],
};

• The cover should be an object that has three keys.
  • name file name. [Optional]
  • data image as blob or base64 dataURI.
• The series and sequence are not recognised by many readers (the Calibre properties are used)
• The genre becomes the main subject in the final EPUB
• The tags also become subjects in the final EPUB
• For published note the year-month-day format
• The language is the short ISO language name (en, fr, de etc)
• The showContents option (default is true) lets you suppress the contents page
• The images array is where you refer to all images used inside the book. Every image should be referenced as an object with three keys.
  • name file name as refenced in the document html, Ex: name: "image-1.png" should be referenced in your html as <img src="../images/image-1.png" />.
  • data image as blob or base64 dataURI.

Call the document method with the aforementioned metadata object detailing your book.

var epub = new NodepubLite(metadata);

You also have the option to generate your own contents page. Full details on this are shown further down the page.

Fill in the content

The bulk of the work is adding your content.

Call addSection on your new document with a title and the HTML contents for each section in turn (usually a section is a chapter), plus extra options as follows.

epub.addSection(
  title,
  content,
  excludeFromContents,
  isFrontMatter,
  overrideFilename
);

PARAMETER	PURPOSE	DEFAULT
title (required)	Table of contents entry
content (required)	HTML body text	-
excludeFromContents	Hide from contents/navigation	false
isFrontMatter	Places before any contents page	false
overrideFilename	Section filename inside the EPUB

For example:

epub.addSection("Copyright", copyright, false, true);
epub.addSection("Chapter 1", "<h1>One</h1><p>...</p>");
epub.addSection(
  "Chapter 2",
  "<h1>One</h1><p>...</p>",
  false,
  false,
  "chapter-2"
);

Excluding from the contents page list allows you to add content which does not appear either in the auto-generated HTML table of contents or the metadata contents used directly by ereaders/software. This is handy for example when adding a page at the end of the book with details of your other books - a common page which may not appear in the book contents.

Flagging as front matter still includes it but passes that flag into any custom content page generation function you may choose to provide. Front matter will also appear in your book ahead of the contents page when read linearly. Useful for dedication pages, for example.

Override the filename within the generated EPUB allows the filename (don't provide an extention) to be specified manually, which enhances internal linking across sections. This was always possible using the auto-generated filenames (eg s2.xhtml) but, whilst the naming was predictable, inserting a new section bumped further sections further along the sequence (so s2 becomes s3 instead), breaking internal links. Using a manually named section prevents that breakage.

This should only be relevant if you are doing those internal cross-section links; general works of fiction for example won't usually need this facility. See the end of chapter one's content and the definition of content two in the example folder for sample usage.

Optionally add some extra CSS

You can inject basic CSS into your book.

epub.addCSS(`p { text-indent: 0; } p+p { text-indent: 0.75em; }`);

You can also choose to make your own custom contents page

A standard contents page is included automatically, but can be overridden. You can also suppress the contents page entirely; see the metadata section above.

You can create your own by passing a second parameter when creating a document - a function which is called when the contents page is being constructed. That function will be given details of all the links, and is expected to return HTML to use for the contents page.

var makeContentsPage = (links) => {
  var contents = "<h1>Chapters</h1>";
  links.forEach((link) => {
    if (link.itemType !== "contents") {
      contents += "<a href='" + link.link + "'>" + link.title + "</a><br />";
    }
  });
  return contents;
};
var epub = new NodepubLite(metadata, makeContentsPage);

The links array which is passed to your callback function consists of objects with the following properties:

• title - the title of the section being linked to
• link - the relative href within the EPUB
• itemType - one of 3 types, those being front for front matter, contents for the contents page, and main for the remaining sections
  • You can use this to omit front matter from the contents page if required

Your callback function should return a string of HTML which will form the body of the contents page. The example.js mentioned in the next section shows this in action.

Generating your EPUB

Note that NodepubLite is asynchronous, actionable using async/await.

// This will generate an epub file `example.epub`
// that will start downloading inside the browser window.
const promise = epub.createEPUB("example").catch(console.error);

Substitutions within your book content

A simple form of text substitution is supported. At any point in your section's content you may include placeholders like [[COPYRIGHT]]. When the EPUB is generated any such placeholders which match the capitalised name of a metadata entry are replaced with the corresponding metadata value.

For example, you could have a "Thanks for Reading" page at the end of your book which has the following markup:

<p>Thanks for reading <strong>[[TITLE]]</strong> by <em>[[AUTHOR]]</em>.</p>

When the EPUB is produced and opened, if your metadata was set as per the book "The Hobbit" by "JRR Tolkien", then it will look like this:

---

Thanks for reading The Hobbit by JRR Tolkien.

---

This means you can re-use content across multiple books, or refer to the author/title/series/whatever at any point within the book without worrying about consistency or maintenance.

Reminder

This is a utility module, not a user-facing one. In other words it is assumed that the caller has already validated the inputs. Only basic omission checks are performed.