@ocelot-consulting/hummus-toc

HummusJS Table of Contents (TOC) creator

This module was created to assist in the creation of TOC's for PDFs, based on a hierarchy of input.

Purpose

When delivered PDF content or generated PDF content, sometimes the hierarchy for navigation is applied separately of the creation process. This module helps augment that original data with a logical hierarchy for navigating the document.

Installation

npm i --save @ocelot-consulting/hummus-toc

Usage

As seen in the test file, once the module is loaded, it merely needs to have the parameters of the input file path, the output file path, and the hierarchy outline JSON.

const path = require('path')
const createTOC = require('@ocelot-consulting/hummus-toc')

const inputFile = path.join(__dirname, 'data', 'existing.pdf')
const outputFile = path.join(__dirname, 'data', 'new.pdf')
const outline = require(path.join(__dirname, 'data', 'outline.json'))

createTOC(inputFile, outputFile, outline)

Hierarchy/Outline Format

The top level of the outline is a JSON array, made up of elements having the following structure:

[{
  "title": "Top Level",
  "page": 5,
  "children": [{
    "title": "Lower Level",
    "page": 4
  }]
}]

Of that, the children property in a given outline object is optional, but contains an array of hierarchy elements at the next sub-level.

Credits

• There is one free font included with the project, "Monkey" by Tommy Ettinger. Wanted a monospaced font that looked interesting, and it fit the bill.

• Huge shout out to the HummusJS project and its maintainer galkahana. It took me awhile going back and forth between the project and the PDF spec, but finally got the concepts nailed down. Also, the sample PDF used in the tests comes from that project.

• I was most of the way there on the code, but then ran into this issue response that helped me get over the goal line. Thanks Speedy37!

• Also leveraged relative hyperlink information from this source. Thanks agentcooper!