Follow Links to Combine Documents

[shellscape]

I'd like to request the ability to instruct the parser to follow file links to other markdown files, to combine multiple documents into one.

[simonhaenisch]

Thanks for the request 🙂 However I think it might be out of scope for this package.

Depending on the platform you're on, it's relatively straight-forward to combine multiple PDFs into one (e. g. on macOS you can use Preview.app and drag-and-drop them together).

There's also lots of apps and other npm packages out there to merge PDFs... try searching for "pdf merge" on npm. Can you please try see if there's any simple solution for this by using another package/cli tool/app?

[TabithaLarkin]

It might be cool if you could pass in a stream into md-to-pdf such as:

concat 1.md 2.md 3.md | md-to-pdf joined.pdf

Otherwise @shellscape you could use concat to join the files to an intermediate one, and then use that in md-to-pdf.

[simonhaenisch]

@StephenLarkin reading from stdin is one thing I want to implement in the next major release 👍 But it'll probably take a bit till I have the time to do it...

[simonhaenisch]

After @gigaga asked for something similar (he suggested a [include](file.md) syntax), one other idea that I had was to use a custom renderer for Marked, because it's already possible to extend the renderer using the marked_options of the config:

const { readFileSync } = require('fs');
const { Renderer } = require('marked');
const getMarked = require('md-to-pdf/lib/get-marked-with-highlighter');

const renderer = new Renderer();

const originalLinkRenderer = renderer.link.bind(renderer);

renderer.link = (href, title, text) => {
  if (text !== 'include') {
    return originalLinkRenderer(href, title, text);
  }

  // 1. read file
  const md = readFileSync(href, 'utf-8');

  // 2. get marked instance that's equivalent to the one from md-to-pdf
  const marked = getMarked(marked_options);

  // 3. convert file to html string
  return marked(md);
};

const marked_options = { renderer };

module.exports = { marked_options };

I made a Gist that you can clone if you want to try it out:

git clone https://gist.github.com/b5c935e76052a40b1e32bfe28673b188 md-to-pdf-includes
cd md-to-pdf-includes
npm install
npm start
open test.pdf

[gigaga]

Thanks a lot! It's perfect!!

[simonhaenisch]

I just made a prerelease of version 3, you can try it out with npm i -g md-to-pdf@next. With that it's now possible to do the above mentioned concatenating:

concat 1.md 2.md 3.md | md-to-pdf

It will generate a file output.pdf in the current working directory. It's not yet possible to pipe the generated pdf into a file, but this will be implemented before the release of v3. Then you can do

concat 1.md 2.md 3.md | md-to-pdf > my-file.pdf