Sunday, August 27, 2017

Citation.js: Endpoint on RunKit

A while back I tweeted about making a simple Citation.js API Endpoint with RunKit.

Using the Express app helper and some type-checking code:

const express = require('@runkit/runkit/express-endpoint/1.0.0')
const app = express(exports)
const Cite = require('citation-js@0.3.0')
const docs = ''

const validStyle = style => ['bibtxt', 'bibtex', 'csl', 'citation'].includes(style) || /^citation-\w+$/.test(style)
const validType = type => ['string', 'html', 'json'].includes(type)

const last = array => array[array.length - 1]

const getOptions = params => {
  const fragments = params.split('/')
  let data, style = 'csl', type = 'html'

  // parse fragments
  // (got pretty complex, as data can contain '/'s)

  return {data, style, type}

.get('/', (_, res) => res.redirect(docs))
.get('/*', ({params: {0: params}}, res) => {
  const {data, style, type} = getOptions(params)
  const cite = new Cite(data)
  const output = cite.get({style, type})

Full code here. Makes an API like this:



  • $CODE is the API id (vf2453q1d6s5 in this case),
  • $DATA is the input data (DOI, Wikidata ID, or even a BibTeX string),
  • $STYLE (optional) is the output style,
  • and $TYPE (optional) is the output type (basically plain text vs html).

This makes it possible to link to a lot of Citation.js outputs:

Citation.js Version 0.3 Released!

It’s been in beta since January 30, but here it is: Citation.js version 0.3. Below I explain the changes since the last blog post, and under that is a more complete change log. Also some upcoming changes.


Recent changes

Custom citation formatting

  • One of the remaining milestones for v0.3.0 was a better API for custom citation formatting, as outlined in the previous post. The exact implementation differs a bit, but is essentially the same. Docs can be found here.


  • Cite#add() and Cite#set() now have asynchronous siblings, Cite#addAsync() and Cite#setAsync().
  • Both async and sync test cases are needed for full coverage, so I won’t just change one into another, as I previously suggested.


  • The BibTeX parser got a big update, improving both the text-parsing code and the JSON-transforming code.
  • The Wikidata issue (sorry for the GIF) is fixed now, and I like the current API and code. The solution is inspired by the recent BibTeX refactoring.

Older changes

Also look at previous blog posts for more info. List goes from newer to older.


  • Code coverage
  • Test case and framework updates
  • DOI support
  • CLI fixes
  • Custom sorting
  • Cite as an Iterator
  • Bib.TXT support
  • Give jQuery.Citation.js its own repository
  • Async support
  • Build size disc & dependency badges
  • Exposing internal functions and splitting up the main file into smaller files
  • Change of some internal Cite properties
  • Using an actual code style and use of ES6+
  • Exposing version numbers


  • CLI bugs
  • Variable name typos
  • Output JSON is now valid JSON (I know, right?)
  • Wikidata ID parsing
  • Cite#getIds()
  • CLI not working
  • Wikidata tests not working
  • CSL not working
  • Browserify not working

Upcoming changes

  • Web scrapers and, Open Graph, etc.
  • Input parsing extensions
  • More coverage
  • More input formats, like better support for BibJSON, and new formats.