markdown-it-fancy-lists


markdown-it-fancy-lists
=======================

Plugin for the markdown-it
markdown parser.

Uses unofficial markdown syntax based on the syntax supported by
Pandoc.
See the section Syntax below for details.

Installation
------
This library can be installed from the NPM package registry. Using NPM:
``
npm install markdown-it-fancy-lists
`
or Yarn
`
yarn add markdown-it-fancy-lists
`

Usage
------
ES module:
`javascript
import * as MarkdownIt from "markdown-it";
import { markdownItFancyListPlugin } from "markdown-it-fancy-lists";

const parser = new MarkdownIt("default");
parser.use(markdownItFancyListPlugin);
parser.render(/ markdown string /);
`

CommonJS:
`javascript
const MarkdownIt = require('markdown-it');
const markdownItFancyListPlugin = require("markdown-it-fancy-lists").markdownItFancyListPlugin;

const parser = new MarkdownIt("default");
parser.use(markdownItFancyListPlugin);
parser.render(/ markdown string /);
`


Syntax
------
The supported markdown syntax is based on the one used by
Pandoc.

A simple example:
`markdown
i. foo
ii. bar
iii. baz
`
The will yield HTML output like:
`html


1. foo


2. bar


3. baz


`

A more complex example:
`markdown
c. charlie
#. delta
iv) subfour
#) subfive
#) subsix
#. echo
`

A short description of the syntactical rules:

* Apart from numbers, also letters (uppercase or lowercase) and
Roman numerals (uppercase or lowercase) can be used to number
ordered list items. Like lists marked with numbers, they need to
be followed by a single right-parenthesis or period.
* Changing list marker types (also between uppercase and lowercase,
or the symbol after the 'number') starts a new list.
* The numeral of the first item determines the numbering of the list.
If the first item is numbered "b", the next item will be numbered
"c", even if it is marked "z" in the source. This corresponds to
the normal markdown-it behavior for numeric lists, and
essentially also implements Pandoc's startnum extension.
* If the first list item is numbered "I" or "i", the list is considered
to be numbered using Roman numerals, starting at 1. If the list
starts with another single letter that could be interpreted as a
Roman numeral, the list is numbered using letters: a first item
marked with "C." uses uppercase letters starting at 3, not Roman
numerals starting a 100.
* In subsequent list items, such symbols can be used without any
ambiguity: in "B.", "C.", "D." the "C" is the letter "C"; in
"IC.", "C.", "CI." the "C" is a Roman 100.
* A "#" may be used in place of any numeral to continue a list. If
the first item in a list is marked with "#", that list is numbered
"1", "2", "3", etc.
* A list marker consisting of a single uppercase letter followed by
a period (including Roman numerals like "I." or "V.") needs to be
followed by at least two spaces (rationale).

All of the above are entirely compatible with how Pandoc works. There
are two small differences with Pandoc's syntax:

* This plugin does not support list numbers enclosed in parentheses,
as the Commonmark spec does not support these either for lists
numbered with Arabic numerals.
* Pandoc does not allow any list to interrupt a paragraph. In the
spirit of the Commonmark spec (which allows only lists starting
with 1 to interrupt a paragraph), this plugins allows lists that
start with "A", "a", "I" or "i" (i.e. all 'first numerals') to
interrupt a paragraph. The same holds for the "#" generic numbered
list item marker.
For nested lists, any start number can interrupt a paragraph.

Configuration
-------------
Options can be provided as a second argument when registering the plugin:
`javascript
parser.use(markdownItFancyListPlugin, {
/ options /
});
`

Supported configuration options:

* allowOrdinal - Whether to allow an ordinal indicator
(º) after the numeral, as occurs in e.g. legal documents (default: false). If this option is enabled,
input like
`markdown
1º. foo
2º. bar
3º. baz
`
will be converted to
`html


1. foo


2. bar


3. baz


`
You will need custom CSS to re-insert the ordinal indicator
into the displayed output based on the ordinal class.

Because the ordinal indicator is commonly confused with other characters like the degree symbol, these
characters are tolerated and considered equivalent to the ordinal indicator.
* allowMultiLetter - Whether to allow multi-letter alphabetic numerals, to number lists beyond 26
(default: false). If this option is enabled, input like
`markdown
AA. foo
AB. bar
AC. baz
`
will be converted to
`html


27. foo


28. bar


29. baz


``
Multi-letter alphabetic numerals can consist of at most 3 characters, which should be enough for a
typical list. When a list starts with a numeral that can be both Roman or multi-letter alphabetic,
like "II", it is considered to be Roman.

Versioning
----------
This project adheres to Semantic Versioning.

Contributing
------------
Contributions to this project are more than welcome. When reporting an issue,
please include the input to reproduce the issue, along with the expected
output. When submitting a PR, please include tests with your changes.

License
-------
This project is released under the MIT license.