HackMD/public/js/reveal-markdown.js

356 lines
12 KiB
JavaScript

/* eslint-env browser, jquery */
import { preventXSS, escapeAttrValue } from './render'
import { md } from './extra'
/**
* The reveal.js markdown plugin. Handles parsing of
* markdown inside of presentations as well as loading
* of external markdown documents.
*/
(function (root, factory) {
if (typeof exports === 'object') {
module.exports = factory()
} else {
// Browser globals (root is window)
root.RevealMarkdown = factory()
root.RevealMarkdown.initialize()
}
}(this, function () {
var DEFAULT_SLIDE_SEPARATOR = '^\r?\n---\r?\n$'
var DEFAULT_NOTES_SEPARATOR = '^note:'
var DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR = '\\.element\\s*?(.+?)$'
var DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR = '\\.slide:\\s*?(\\S.+?)$'
var SCRIPT_END_PLACEHOLDER = '__SCRIPT_END__'
/**
* Retrieves the markdown contents of a slide section
* element. Normalizes leading tabs/whitespace.
*/
function getMarkdownFromSlide (section) {
var template = section.querySelector('script')
// strip leading whitespace so it isn't evaluated as code
var text = (template || section).textContent
// restore script end tags
text = text.replace(new RegExp(SCRIPT_END_PLACEHOLDER, 'g'), '</script>')
var leadingWs = text.match(/^\n?(\s*)/)[1].length
var leadingTabs = text.match(/^\n?(\t*)/)[1].length
if (leadingTabs > 0) {
text = text.replace(new RegExp('\\n?\\t{' + leadingTabs + '}', 'g'), '\n')
} else if (leadingWs > 1) {
text = text.replace(new RegExp('\\n? {' + leadingWs + '}', 'g'), '\n')
}
return text
}
/**
* Given a markdown slide section element, this will
* return all arguments that aren't related to markdown
* parsing. Used to forward any other user-defined arguments
* to the output markdown slide.
*/
function getForwardedAttributes (section) {
var attributes = section.attributes
var result = []
for (var i = 0, len = attributes.length; i < len; i++) {
var name = attributes[i].name
var value = attributes[i].value
// disregard attributes that are used for markdown loading/parsing
if (/data-(markdown|separator|vertical|notes)/gi.test(name)) continue
if (value) {
result.push(name + '="' + value + '"')
} else {
result.push(name)
}
}
return result.join(' ')
}
/**
* Inspects the given options and fills out default
* values for what's not defined.
*/
function getSlidifyOptions (options) {
options = options || {}
options.separator = options.separator || DEFAULT_SLIDE_SEPARATOR
options.notesSeparator = options.notesSeparator || DEFAULT_NOTES_SEPARATOR
options.attributes = options.attributes || ''
return options
}
/**
* Helper function for constructing a markdown slide.
*/
function createMarkdownSlide (content, options) {
options = getSlidifyOptions(options)
var notesMatch = content.split(new RegExp(options.notesSeparator, 'mgi'))
if (notesMatch.length === 2) {
content = notesMatch[0] + '<aside class="notes" data-markdown>' + notesMatch[1].trim() + '</aside>'
}
// prevent script end tags in the content from interfering
// with parsing
content = content.replace(/<\/script>/g, SCRIPT_END_PLACEHOLDER)
return '<script type="text/template">' + content + '</script>'
}
/**
* Parses a data string into multiple slides based
* on the passed in separator arguments.
*/
function slidify (markdown, options) {
options = getSlidifyOptions(options)
var separatorRegex = new RegExp(options.separator + (options.verticalSeparator ? '|' + options.verticalSeparator : ''), 'mg')
var horizontalSeparatorRegex = new RegExp(options.separator)
var matches
var lastIndex = 0
var isHorizontal
var wasHorizontal = true
var content
var sectionStack = []
// iterate until all blocks between separators are stacked up
while ((matches = separatorRegex.exec(markdown)) !== null) {
// determine direction (horizontal by default)
isHorizontal = horizontalSeparatorRegex.test(matches[0])
if (!isHorizontal && wasHorizontal) {
// create vertical stack
sectionStack.push([])
}
// pluck slide content from markdown input
content = markdown.substring(lastIndex, matches.index)
if (isHorizontal && wasHorizontal) {
// add to horizontal stack
sectionStack.push(content)
} else {
// add to vertical stack
sectionStack[sectionStack.length - 1].push(content)
}
lastIndex = separatorRegex.lastIndex
wasHorizontal = isHorizontal
}
// add the remaining slide
(wasHorizontal ? sectionStack : sectionStack[sectionStack.length - 1]).push(markdown.substring(lastIndex))
var markdownSections = ''
// flatten the hierarchical stack, and insert <section data-markdown> tags
for (var i = 0, len = sectionStack.length; i < len; i++) {
// vertical
if (sectionStack[i] instanceof Array) {
markdownSections += '<section ' + options.attributes + '>'
sectionStack[i].forEach(function (child) {
markdownSections += '<section data-markdown>' + createMarkdownSlide(child, options) + '</section>'
})
markdownSections += '</section>'
} else {
markdownSections += '<section ' + options.attributes + ' data-markdown>' + createMarkdownSlide(sectionStack[i], options) + '</section>'
}
}
return markdownSections
}
/**
* Parses any current data-markdown slides, splits
* multi-slide markdown into separate sections and
* handles loading of external markdown.
*/
function processSlides () {
var sections = document.querySelectorAll('[data-markdown]')
var section
for (var i = 0, len = sections.length; i < len; i++) {
section = sections[i]
if (section.getAttribute('data-markdown').length) {
var xhr = new XMLHttpRequest()
var url = section.getAttribute('data-markdown')
var datacharset = section.getAttribute('data-charset')
// see https://developer.mozilla.org/en-US/docs/Web/API/element.getAttribute#Notes
if (datacharset !== null && datacharset !== '') {
xhr.overrideMimeType('text/html; charset=' + datacharset)
}
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
// file protocol yields status code 0 (useful for local debug, mobile applications etc.)
if ((xhr.status >= 200 && xhr.status < 300) || xhr.status === 0) {
section.outerHTML = slidify(xhr.responseText, {
separator: section.getAttribute('data-separator'),
verticalSeparator: section.getAttribute('data-separator-vertical'),
notesSeparator: section.getAttribute('data-separator-notes'),
attributes: getForwardedAttributes(section)
})
} else {
section.outerHTML = '<section data-state="alert">' +
'ERROR: The attempt to fetch ' + url + ' failed with HTTP status ' + xhr.status + '.' +
'Check your browser\'s JavaScript console for more details.' +
'<p>Remember that you need to serve the presentation HTML from a HTTP server.</p>' +
'</section>'
}
}
}
xhr.open('GET', url, false)
try {
xhr.send()
} catch (e) {
alert('Failed to get the Markdown file ' + url + '. Make sure that the presentation and the file are served by a HTTP server and the file can be found there. ' + e)
}
} else if (section.getAttribute('data-separator') || section.getAttribute('data-separator-vertical') || section.getAttribute('data-separator-notes')) {
section.outerHTML = slidify(getMarkdownFromSlide(section), {
separator: section.getAttribute('data-separator'),
verticalSeparator: section.getAttribute('data-separator-vertical'),
notesSeparator: section.getAttribute('data-separator-notes'),
attributes: getForwardedAttributes(section)
})
} else {
section.innerHTML = createMarkdownSlide(getMarkdownFromSlide(section))
}
}
}
/**
* Check if a node value has the attributes pattern.
* If yes, extract it and add that value as one or several attributes
* the the terget element.
*
* You need Cache Killer on Chrome to see the effect on any FOM transformation
* directly on refresh (F5)
* http://stackoverflow.com/questions/5690269/disabling-chrome-cache-for-website-development/7000899#answer-11786277
*/
function addAttributeInElement (node, elementTarget, separator) {
var mardownClassesInElementsRegex = new RegExp(separator, 'mg')
var mardownClassRegex = new RegExp('([^"= ]+?)="([^"=]+?)"', 'mg')
var nodeValue = node.nodeValue
var matches
var matchesClass
if ((matches = mardownClassesInElementsRegex.exec(nodeValue))) {
var classes = matches[1]
nodeValue = nodeValue.substring(0, matches.index) + nodeValue.substring(mardownClassesInElementsRegex.lastIndex)
node.nodeValue = nodeValue
while ((matchesClass = mardownClassRegex.exec(classes))) {
var name = matchesClass[1]
var value = matchesClass[2]
if (name.substr(0, 5) === 'data-' || window.whiteListAttr.indexOf(name) !== -1) { elementTarget.setAttribute(name, escapeAttrValue(value)) }
}
return true
}
return false
}
/**
* Add attributes to the parent element of a text node,
* or the element of an attribute node.
*/
function addAttributes (section, element, previousElement, separatorElementAttributes, separatorSectionAttributes) {
if (element != null && element.childNodes !== undefined && element.childNodes.length > 0) {
var previousParentElement = element
for (var i = 0; i < element.childNodes.length; i++) {
var childElement = element.childNodes[i]
if (i > 0) {
let j = i - 1
while (j >= 0) {
var aPreviousChildElement = element.childNodes[j]
if (typeof aPreviousChildElement.setAttribute === 'function' && aPreviousChildElement.tagName !== 'BR') {
previousParentElement = aPreviousChildElement
break
}
j = j - 1
}
}
var parentSection = section
if (childElement.nodeName === 'section') {
parentSection = childElement
previousParentElement = childElement
}
if (typeof childElement.setAttribute === 'function' || childElement.nodeType === Node.COMMENT_NODE) {
addAttributes(parentSection, childElement, previousParentElement, separatorElementAttributes, separatorSectionAttributes)
}
}
}
if (element.nodeType === Node.COMMENT_NODE) {
if (addAttributeInElement(element, previousElement, separatorElementAttributes) === false) {
addAttributeInElement(element, section, separatorSectionAttributes)
}
}
}
/**
* Converts any current data-markdown slides in the
* DOM to HTML.
*/
function convertSlides () {
var sections = document.querySelectorAll('[data-markdown]')
for (var i = 0, len = sections.length; i < len; i++) {
var section = sections[i]
// Only parse the same slide once
if (!section.getAttribute('data-markdown-parsed')) {
section.setAttribute('data-markdown-parsed', true)
var notes = section.querySelector('aside.notes')
var markdown = getMarkdownFromSlide(section)
markdown = markdown.replace(/&lt;/g, '<').replace(/&gt;/g, '>')
var rendered = md.render(markdown)
rendered = preventXSS(rendered)
var result = window.postProcess(rendered)
section.innerHTML = result[0].outerHTML
addAttributes(section, section, null, section.getAttribute('data-element-attributes') ||
section.parentNode.getAttribute('data-element-attributes') ||
DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR,
section.getAttribute('data-attributes') ||
section.parentNode.getAttribute('data-attributes') ||
DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR)
// If there were notes, we need to re-add them after
// having overwritten the section's HTML
if (notes) {
section.appendChild(notes)
}
}
}
}
// API
return {
initialize: function () {
processSlides()
convertSlides()
},
// TODO: Do these belong in the API?
processSlides: processSlides,
convertSlides: convertSlides,
slidify: slidify
}
}))