311 lines
11 KiB
JavaScript
311 lines
11 KiB
JavaScript
/**
|
||
* @typedef {import('micromark-util-types').HtmlExtension} HtmlExtension
|
||
*/
|
||
|
||
/**
|
||
* @callback BackLabelTemplate
|
||
* Generate a back label dynamically.
|
||
*
|
||
* For the following markdown:
|
||
*
|
||
* ```markdown
|
||
* Alpha[^micromark], bravo[^micromark], and charlie[^remark].
|
||
*
|
||
* [^remark]: things about remark
|
||
* [^micromark]: things about micromark
|
||
* ```
|
||
*
|
||
* This function will be called with:
|
||
*
|
||
* * `0` and `0` for the backreference from `things about micromark` to
|
||
* `alpha`, as it is the first used definition, and the first call to it
|
||
* * `0` and `1` for the backreference from `things about micromark` to
|
||
* `bravo`, as it is the first used definition, and the second call to it
|
||
* * `1` and `0` for the backreference from `things about remark` to
|
||
* `charlie`, as it is the second used definition
|
||
* @param {number} referenceIndex
|
||
* Index of the definition in the order that they are first referenced,
|
||
* 0-indexed.
|
||
* @param {number} rereferenceIndex
|
||
* Index of calls to the same definition, 0-indexed.
|
||
* @returns {string}
|
||
* Back label to use when linking back from definitions to their reference.
|
||
*/
|
||
|
||
/**
|
||
* @typedef Options
|
||
* Configuration.
|
||
* @property {string | null | undefined} [clobberPrefix='user-content-']
|
||
* Prefix to use before the `id` attribute on footnotes to prevent them from
|
||
* *clobbering* (default: `'user-content-'`).
|
||
*
|
||
* Pass `''` for trusted markdown and when you are careful with
|
||
* polyfilling.
|
||
* You could pass a different prefix.
|
||
*
|
||
* DOM clobbering is this:
|
||
*
|
||
* ```html
|
||
* <p id="x"></p>
|
||
* <script>alert(x) // `x` now refers to the `p#x` DOM element</script>
|
||
* ```
|
||
*
|
||
* The above example shows that elements are made available by browsers, by
|
||
* their ID, on the `window` object.
|
||
* This is a security risk because you might be expecting some other variable
|
||
* at that place.
|
||
* It can also break polyfills.
|
||
* Using a prefix solves these problems.
|
||
* @property {string | null | undefined} [label='Footnotes']
|
||
* Textual label to use for the footnotes section (default: `'Footnotes'`).
|
||
*
|
||
* Change it when the markdown is not in English.
|
||
*
|
||
* This label is typically hidden visually (assuming a `sr-only` CSS class
|
||
* is defined that does that) and so affects screen readers only.
|
||
* If you do have such a class, but want to show this section to everyone,
|
||
* pass different attributes with the `labelAttributes` option.
|
||
* @property {string | null | undefined} [labelAttributes='class="sr-only"']
|
||
* Attributes to use on the footnote label (default: `'class="sr-only"'`).
|
||
*
|
||
* Change it to show the label and add other attributes.
|
||
*
|
||
* This label is typically hidden visually (assuming an `sr-only` CSS class
|
||
* is defined that does that) and so affects screen readers only.
|
||
* If you do have such a class, but want to show this section to everyone,
|
||
* pass an empty string.
|
||
* You can also add different attributes.
|
||
*
|
||
* > 👉 **Note**: `id="footnote-label"` is always added, because footnote
|
||
* > calls use it with `aria-describedby` to provide an accessible label.
|
||
* @property {string | null | undefined} [labelTagName='h2']
|
||
* HTML tag name to use for the footnote label element (default: `'h2'`).
|
||
*
|
||
* Change it to match your document structure.
|
||
*
|
||
* This label is typically hidden visually (assuming a `sr-only` CSS class
|
||
* is defined that does that) and so affects screen readers only.
|
||
* If you do have such a class, but want to show this section to everyone,
|
||
* pass different attributes with the `labelAttributes` option.
|
||
* @property {BackLabelTemplate | string | null | undefined} [backLabel]
|
||
* Textual label to describe the backreference back to references (default:
|
||
* `defaultBackLabel`).
|
||
*
|
||
* The default value is:
|
||
*
|
||
* ```js
|
||
* function defaultBackLabel(referenceIndex, rereferenceIndex) {
|
||
* return (
|
||
* 'Back to reference ' +
|
||
* (referenceIndex + 1) +
|
||
* (rereferenceIndex > 1 ? '-' + rereferenceIndex : '')
|
||
* )
|
||
* }
|
||
* ```
|
||
*
|
||
* Change it when the markdown is not in English.
|
||
*
|
||
* This label is used in the `aria-label` attribute on each backreference
|
||
* (the `↩` links).
|
||
* It affects users of assistive technology.
|
||
*/
|
||
|
||
import {normalizeIdentifier} from 'micromark-util-normalize-identifier'
|
||
import {sanitizeUri} from 'micromark-util-sanitize-uri'
|
||
const own = {}.hasOwnProperty
|
||
|
||
/** @type {Options} */
|
||
const emptyOptions = {}
|
||
|
||
/**
|
||
* Generate the default label that GitHub uses on backreferences.
|
||
*
|
||
* @param {number} referenceIndex
|
||
* Index of the definition in the order that they are first referenced,
|
||
* 0-indexed.
|
||
* @param {number} rereferenceIndex
|
||
* Index of calls to the same definition, 0-indexed.
|
||
* @returns {string}
|
||
* Default label.
|
||
*/
|
||
export function defaultBackLabel(referenceIndex, rereferenceIndex) {
|
||
return (
|
||
'Back to reference ' +
|
||
(referenceIndex + 1) +
|
||
(rereferenceIndex > 1 ? '-' + rereferenceIndex : '')
|
||
)
|
||
}
|
||
|
||
/**
|
||
* Create an extension for `micromark` to support GFM footnotes when
|
||
* serializing to HTML.
|
||
*
|
||
* @param {Options | null | undefined} [options={}]
|
||
* Configuration (optional).
|
||
* @returns {HtmlExtension}
|
||
* Extension for `micromark` that can be passed in `htmlExtensions` to
|
||
* support GFM footnotes when serializing to HTML.
|
||
*/
|
||
export function gfmFootnoteHtml(options) {
|
||
const config = options || emptyOptions
|
||
const label = config.label || 'Footnotes'
|
||
const labelTagName = config.labelTagName || 'h2'
|
||
const labelAttributes =
|
||
config.labelAttributes === null || config.labelAttributes === undefined
|
||
? 'class="sr-only"'
|
||
: config.labelAttributes
|
||
const backLabel = config.backLabel || defaultBackLabel
|
||
const clobberPrefix =
|
||
config.clobberPrefix === null || config.clobberPrefix === undefined
|
||
? 'user-content-'
|
||
: config.clobberPrefix
|
||
return {
|
||
enter: {
|
||
gfmFootnoteDefinition() {
|
||
const stack = this.getData('tightStack')
|
||
stack.push(false)
|
||
},
|
||
gfmFootnoteDefinitionLabelString() {
|
||
this.buffer()
|
||
},
|
||
gfmFootnoteCallString() {
|
||
this.buffer()
|
||
}
|
||
},
|
||
exit: {
|
||
gfmFootnoteDefinition() {
|
||
let definitions = this.getData('gfmFootnoteDefinitions')
|
||
const footnoteStack = this.getData('gfmFootnoteDefinitionStack')
|
||
const tightStack = this.getData('tightStack')
|
||
const current = footnoteStack.pop()
|
||
const value = this.resume()
|
||
if (!definitions) {
|
||
this.setData('gfmFootnoteDefinitions', (definitions = {}))
|
||
}
|
||
if (!own.call(definitions, current)) definitions[current] = value
|
||
tightStack.pop()
|
||
this.setData('slurpOneLineEnding', true)
|
||
// “Hack” to prevent a line ending from showing up if we’re in a definition in
|
||
// an empty list item.
|
||
this.setData('lastWasTag')
|
||
},
|
||
gfmFootnoteDefinitionLabelString(token) {
|
||
let footnoteStack = this.getData('gfmFootnoteDefinitionStack')
|
||
if (!footnoteStack) {
|
||
this.setData('gfmFootnoteDefinitionStack', (footnoteStack = []))
|
||
}
|
||
footnoteStack.push(normalizeIdentifier(this.sliceSerialize(token)))
|
||
this.resume() // Drop the label.
|
||
this.buffer() // Get ready for a value.
|
||
},
|
||
|
||
gfmFootnoteCallString(token) {
|
||
let calls = this.getData('gfmFootnoteCallOrder')
|
||
let counts = this.getData('gfmFootnoteCallCounts')
|
||
const id = normalizeIdentifier(this.sliceSerialize(token))
|
||
/** @type {number} */
|
||
let counter
|
||
this.resume()
|
||
if (!calls) this.setData('gfmFootnoteCallOrder', (calls = []))
|
||
if (!counts) this.setData('gfmFootnoteCallCounts', (counts = {}))
|
||
const index = calls.indexOf(id)
|
||
const safeId = sanitizeUri(id.toLowerCase())
|
||
if (index === -1) {
|
||
calls.push(id)
|
||
counts[id] = 1
|
||
counter = calls.length
|
||
} else {
|
||
counts[id]++
|
||
counter = index + 1
|
||
}
|
||
const reuseCounter = counts[id]
|
||
this.tag(
|
||
'<sup><a href="#' +
|
||
clobberPrefix +
|
||
'fn-' +
|
||
safeId +
|
||
'" id="' +
|
||
clobberPrefix +
|
||
'fnref-' +
|
||
safeId +
|
||
(reuseCounter > 1 ? '-' + reuseCounter : '') +
|
||
'" data-footnote-ref="" aria-describedby="footnote-label">' +
|
||
String(counter) +
|
||
'</a></sup>'
|
||
)
|
||
},
|
||
null() {
|
||
const calls = this.getData('gfmFootnoteCallOrder') || []
|
||
const counts = this.getData('gfmFootnoteCallCounts') || {}
|
||
const definitions = this.getData('gfmFootnoteDefinitions') || {}
|
||
let index = -1
|
||
if (calls.length > 0) {
|
||
this.lineEndingIfNeeded()
|
||
this.tag(
|
||
'<section data-footnotes="" class="footnotes"><' +
|
||
labelTagName +
|
||
' id="footnote-label"' +
|
||
(labelAttributes ? ' ' + labelAttributes : '') +
|
||
'>'
|
||
)
|
||
this.raw(this.encode(label))
|
||
this.tag('</' + labelTagName + '>')
|
||
this.lineEndingIfNeeded()
|
||
this.tag('<ol>')
|
||
}
|
||
while (++index < calls.length) {
|
||
// Called definitions are always defined.
|
||
const id = calls[index]
|
||
const safeId = sanitizeUri(id.toLowerCase())
|
||
let referenceIndex = 0
|
||
/** @type {Array<string>} */
|
||
const references = []
|
||
while (++referenceIndex <= counts[id]) {
|
||
references.push(
|
||
'<a href="#' +
|
||
clobberPrefix +
|
||
'fnref-' +
|
||
safeId +
|
||
(referenceIndex > 1 ? '-' + referenceIndex : '') +
|
||
'" data-footnote-backref="" aria-label="' +
|
||
this.encode(
|
||
typeof backLabel === 'string'
|
||
? backLabel
|
||
: backLabel(index, referenceIndex)
|
||
) +
|
||
'" class="data-footnote-backref">↩' +
|
||
(referenceIndex > 1
|
||
? '<sup>' + referenceIndex + '</sup>'
|
||
: '') +
|
||
'</a>'
|
||
)
|
||
}
|
||
const reference = references.join(' ')
|
||
let injected = false
|
||
this.lineEndingIfNeeded()
|
||
this.tag('<li id="' + clobberPrefix + 'fn-' + safeId + '">')
|
||
this.lineEndingIfNeeded()
|
||
this.tag(
|
||
definitions[id].replace(/<\/p>(?:\r?\n|\r)?$/, function ($0) {
|
||
injected = true
|
||
return ' ' + reference + $0
|
||
})
|
||
)
|
||
if (!injected) {
|
||
this.lineEndingIfNeeded()
|
||
this.tag(reference)
|
||
}
|
||
this.lineEndingIfNeeded()
|
||
this.tag('</li>')
|
||
}
|
||
if (calls.length > 0) {
|
||
this.lineEndingIfNeeded()
|
||
this.tag('</ol>')
|
||
this.lineEndingIfNeeded()
|
||
this.tag('</section>')
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|