Demo: Dynamic Citations

Frank Bennett

---

Dynamic Editing

Style:

This page demonstrates dynamic citation editing in the browser. The underlying code was prepared in response to work by Derek Sifford. Click on the chevrons to open a citation widget,  select one or more references, and press “Save” to add them to the document.  Use the pulldown list above to transform the document to another style.  Click on the “More” button below for information on running the code locally, and on adapting it for use in production. 

Running locally

One of the main purposes of this page is to provide a worked example for developers. A good way to explore the way it all works is to run the page locally. Here is how to set that up.

Requirements

• git
• node.js
• npm
• Sphinx

Local setup

Fetch the repo

Clone the citeproc-js documentation project and enter its top-level directory:

git clone https://github.com/Juris-M/citeproc-js-docs.git --recursive
cd citeproc-js-docs

Build the docs

The following command should work:

make html

Run a server using node.js

The built page uses XMLHttpRequest() calls, so it must be viewed through a web server. To run a simple server using node.js, an incantation like this should do the trick:

npm install -g http-server
http-server _build/html

Source File Overview

_static/js/citeproc.js

The citeproc-js CSL processor for Citation Style Language (CSL) stylesheets.

_static/js/citesupport-es5.js

A middleware module that connects the processor, which runs in a web worker, with the DOM of the page.

_static/js/citeworker.js

A web worker to run the processor. This supplies data I/O methods required by the processor, and implements a simple messaging interface for purposes of the demo page.

_static/css/screen.css

CSS code for the citeproc-js documentation, including the demo pages.

_static/data/items

A few sample items for the editing demo, in CSL JSON format.

_static/data/locales

The standard CSL locales.

_static/data/styles

The CSL styles used in the demo. The “JM” styles are from the Juris-M styles repository, and have modular legal style support. The remainder are from the official CSL repository, which feeds the Zotero styles distribution site.

_static/data/juris

A set of legal style modules resides here. For information on legal style support in CSL-M (multilingual-enhanced CSL) see the Juris-M Style Editor (GitHub account required).

Integrator notes

Here are some notes on things relevant to deployment:

• The class should be instantiated as citesupport. The event handlers expect the class object to be available in global context under that name.
• If config.demo is true, the stored object citationIdToPos maps citationIDs to the index position of fixed “pegs” in the document that have class citeme. In the demo, this map is stored in localStorage, and is used to reconstruct the document state (by reinserting class:citation span tags) on page reload.
• If config.demo is false, the document is assumed to contain class:citation span tags, and operations on citeme nodes will not be performed. In non-demo mode, citationIdToPos carries the index position of citation nodes for good measure, but the mapping is not used for anything.
• The spoofDocument() function brings citation data into memory. In the demo, this data is held in localStorage, and spoofDocument() performs some sanity checks on data and document. For a production deployment, this is the place for code that initially extracts citation data the document (if, for example, it is stashed in data-attributes on citation nodes).
• The setCitations() function is where citation data for individual citations would be saved, at the location marked by NOTE.
• The user-interface functions buildStyleMenu() and citationWidget() are simple things cast for the demo, and should be replaced with something a bit more functional.
• The SafeStorage class should be replaced (or subclassed?) for deployment with a class that provides the same methods. If the citation objects making up citationByIndex are stored directly on the class:citation span nodes, the getter for that value should harvest the values from the nodes, and store them on config.citationByIndex. The setter should set config.citationByIndex only, relying on other code to update the node value.
• Probably some other stuff that I’ve overlooked.

Worker API

The heavy lifting is done by the CSL processor, which runs in a separate thread as a web worker. Only the document-facing interface of the worker is described here: it should not be necessary to tangle with the internals of the worker itself. Its only idiosyncracy is that it assigns note numbers (reflected in the return) in citation sequence—in contrast to word processor context, it assumes that the only footnotes in the document are those generated automatically by a note style. If that is not true in your context, you will want to disable that behavior, and do whatever is necessary on document side to extract real note numbers for delivery to the processor.

The worker is controlled by two methods, callInitProcessor() and callRegisterCitation(), each with a corresponding message and return event.

citesupport.callInitProcessor(styleID, localeID)

This method is used on page load, on change of style, and when all citations have been removed from the document. The styleID argument is mandatory. If localeID is not provided, the processor will be configured with the en-US locale.

The citesupport.callInitProcessor method implicitly accesses the config.citationByIndex array, which must be accessible in page context. If the array is empty, the processor will be initialized without citations. If the array contains citations, the processor will be initialized to that document state, and return an array of arrays as rebuildData, for use in reconstructing citations in the document text. Each sub-array contains a citation ID, a note number, and a citation string. For example, if the styleID is for a note style, and if config.citationByIndex yields the citations “Wurzel Gummidge (1990)” and “My Aunt Sally (2001),” the rebuildData structure would look like this:

[
    [
       "lu7Tu3ki",
       "1",
       "Wurzel Gummidge (1990)"
    ],
    [
       "ko4aNoo9",
       "2",
       "My Aunt Sally (2001)"

    ]
]

citesupport.callRegisterCitation(citation, preCitations, postCitations)

This method is used to add or to edit citations. All three arguments are mandatory. citation is an ordinary citation object as described above. preCitations and postCitations are arrays of arrays, in which each sub-array is composed of a citation ID and a note number. For example, if a note citation is to be inserted between the “Wurzel Gummidge” and “Aunt Sally” citations in the example above, these would have the following form:

preCitations = [
    [
        "lu7Tu3ki",
        "1"
    ]
];

postCitations = [
    [
        "ko4aNoo9",
        "3"
    ]
];

Notice the change to the note number: the processor registers note numbers for use in back-references, but maintenance of correct note numbering must be handled in document-side code.

The citesupport.callRegisterCitation method returns two values from the processor: citationByIndex (described above) and citations. The latter is an array of one or more arrays, each composed of a citation position index, a string, and a citation ID. For example, the return value to insert a citation “Calvin (1995); Hobbes (2016)” between the “Wurzel Gummidge” and “My Aunt Sally” citations would look something like this:

[
   [
       1,
       "Calvin (1995); Hobbes (2016)",
       "Ith7eg8T"
   ]
]

Note that the return value might contain updates for multiple citations.