519 lines
15 KiB
JavaScript
Executable File
519 lines
15 KiB
JavaScript
Executable File
/*!
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* The reveal.js markdown plugin. Handles parsing of
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* markdown inside of presentations as well as loading
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* of external markdown documents.
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*/
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import { marked } from "marked";
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const DEFAULT_SLIDE_SEPARATOR = "\r?\n---\r?\n",
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DEFAULT_NOTES_SEPARATOR = "notes?:",
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DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR = "\\.element\\s*?(.+?)$",
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DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR = "\\.slide:\\s*?(\\S.+?)$";
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const SCRIPT_END_PLACEHOLDER = "__SCRIPT_END__";
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const CODE_LINE_NUMBER_REGEX = /\[([\s\d,|-]*)\]/;
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const HTML_ESCAPE_MAP = {
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"&": "&",
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"<": "<",
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">": ">",
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'"': """,
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"'": "'",
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};
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const Plugin = () => {
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// The reveal.js instance this plugin is attached to
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let deck;
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/**
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* Retrieves the markdown contents of a slide section
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* element. Normalizes leading tabs/whitespace.
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*/
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function getMarkdownFromSlide(section) {
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// look for a <script> or <textarea data-template> wrapper
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var template =
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section.querySelector("[data-template]") ||
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section.querySelector("script");
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// strip leading whitespace so it isn't evaluated as code
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var text = (template || section).textContent;
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// restore script end tags
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text = text.replace(new RegExp(SCRIPT_END_PLACEHOLDER, "g"), "</script>");
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var leadingWs = text.match(/^\n?(\s*)/)[1].length,
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leadingTabs = text.match(/^\n?(\t*)/)[1].length;
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if (leadingTabs > 0) {
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text = text.replace(
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new RegExp("\\n?\\t{" + leadingTabs + "}(.*)", "g"),
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function (m, p1) {
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return "\n" + p1;
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}
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);
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} else if (leadingWs > 1) {
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text = text.replace(
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new RegExp("\\n? {" + leadingWs + "}(.*)", "g"),
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function (m, p1) {
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return "\n" + p1;
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}
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);
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}
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return text;
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}
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/**
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* Given a markdown slide section element, this will
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* return all arguments that aren't related to markdown
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* parsing. Used to forward any other user-defined arguments
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* to the output markdown slide.
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*/
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function getForwardedAttributes(section) {
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var attributes = section.attributes;
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var result = [];
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for (var i = 0, len = attributes.length; i < len; i++) {
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var name = attributes[i].name,
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value = attributes[i].value;
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// disregard attributes that are used for markdown loading/parsing
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if (/data\-(markdown|separator|vertical|notes)/gi.test(name)) continue;
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if (value) {
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result.push(name + '="' + value + '"');
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} else {
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result.push(name);
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}
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}
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return result.join(" ");
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}
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/**
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* Inspects the given options and fills out default
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* values for what's not defined.
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*/
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function getSlidifyOptions(options) {
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options = options || {};
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options.separator = options.separator || DEFAULT_SLIDE_SEPARATOR;
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options.notesSeparator = options.notesSeparator || DEFAULT_NOTES_SEPARATOR;
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options.attributes = options.attributes || "";
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return options;
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}
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/**
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* Helper function for constructing a markdown slide.
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*/
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function createMarkdownSlide(content, options) {
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options = getSlidifyOptions(options);
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var notesMatch = content.split(new RegExp(options.notesSeparator, "mgi"));
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if (notesMatch.length === 2) {
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content =
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notesMatch[0] +
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'<aside class="notes">' +
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marked(notesMatch[1].trim()) +
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"</aside>";
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}
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// prevent script end tags in the content from interfering
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// with parsing
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content = content.replace(/<\/script>/g, SCRIPT_END_PLACEHOLDER);
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return '<script type="text/template">' + content + "</script>";
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}
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/**
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* Parses a data string into multiple slides based
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* on the passed in separator arguments.
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*/
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function slidify(markdown, options) {
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options = getSlidifyOptions(options);
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var separatorRegex = new RegExp(
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options.separator +
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(options.verticalSeparator ? "|" + options.verticalSeparator : ""),
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"mg"
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),
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horizontalSeparatorRegex = new RegExp(options.separator);
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var matches,
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lastIndex = 0,
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isHorizontal,
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wasHorizontal = true,
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content,
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sectionStack = [];
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// iterate until all blocks between separators are stacked up
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while ((matches = separatorRegex.exec(markdown))) {
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var notes = null;
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// determine direction (horizontal by default)
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isHorizontal = horizontalSeparatorRegex.test(matches[0]);
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if (!isHorizontal && wasHorizontal) {
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// create vertical stack
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sectionStack.push([]);
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}
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// pluck slide content from markdown input
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content = markdown.substring(lastIndex, matches.index);
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if (isHorizontal && wasHorizontal) {
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// add to horizontal stack
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sectionStack.push(content);
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} else {
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// add to vertical stack
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sectionStack[sectionStack.length - 1].push(content);
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}
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lastIndex = separatorRegex.lastIndex;
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wasHorizontal = isHorizontal;
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}
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// add the remaining slide
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(wasHorizontal ? sectionStack : sectionStack[sectionStack.length - 1]).push(
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markdown.substring(lastIndex)
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);
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var markdownSections = "";
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// flatten the hierarchical stack, and insert <section data-markdown> tags
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for (var i = 0, len = sectionStack.length; i < len; i++) {
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// vertical
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if (sectionStack[i] instanceof Array) {
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markdownSections += "<section " + options.attributes + ">";
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sectionStack[i].forEach(function (child) {
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markdownSections +=
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"<section data-markdown>" +
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createMarkdownSlide(child, options) +
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"</section>";
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});
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markdownSections += "</section>";
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} else {
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markdownSections +=
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"<section " +
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options.attributes +
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" data-markdown>" +
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createMarkdownSlide(sectionStack[i], options) +
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"</section>";
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}
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}
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return markdownSections;
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}
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/**
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* Parses any current data-markdown slides, splits
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* multi-slide markdown into separate sections and
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* handles loading of external markdown.
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*/
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function processSlides(scope) {
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return new Promise(function (resolve) {
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var externalPromises = [];
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[].slice
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.call(
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scope.querySelectorAll(
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"section[data-markdown]:not([data-markdown-parsed])"
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)
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)
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.forEach(function (section, i) {
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if (section.getAttribute("data-markdown").length) {
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externalPromises.push(
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loadExternalMarkdown(section).then(
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// Finished loading external file
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function (xhr, url) {
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section.outerHTML = slidify(xhr.responseText, {
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separator: section.getAttribute("data-separator"),
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verticalSeparator: section.getAttribute(
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"data-separator-vertical"
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),
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notesSeparator: section.getAttribute(
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"data-separator-notes"
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),
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attributes: getForwardedAttributes(section),
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});
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},
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// Failed to load markdown
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function (xhr, url) {
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section.outerHTML =
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'<section data-state="alert">' +
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"ERROR: The attempt to fetch " +
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url +
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" failed with HTTP status " +
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xhr.status +
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"." +
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"Check your browser's JavaScript console for more details." +
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"<p>Remember that you need to serve the presentation HTML from a HTTP server.</p>" +
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"</section>";
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}
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)
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);
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} else {
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section.outerHTML = slidify(getMarkdownFromSlide(section), {
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separator: section.getAttribute("data-separator"),
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verticalSeparator: section.getAttribute(
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"data-separator-vertical"
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),
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notesSeparator: section.getAttribute("data-separator-notes"),
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attributes: getForwardedAttributes(section),
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});
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}
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});
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Promise.all(externalPromises).then(resolve);
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});
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}
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function loadExternalMarkdown(section) {
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return new Promise(function (resolve, reject) {
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var xhr = new XMLHttpRequest(),
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url = section.getAttribute("data-markdown");
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var datacharset = section.getAttribute("data-charset");
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// see https://developer.mozilla.org/en-US/docs/Web/API/element.getAttribute#Notes
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if (datacharset != null && datacharset != "") {
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xhr.overrideMimeType("text/html; charset=" + datacharset);
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}
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xhr.onreadystatechange = function (section, xhr) {
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if (xhr.readyState === 4) {
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// file protocol yields status code 0 (useful for local debug, mobile applications etc.)
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if ((xhr.status >= 200 && xhr.status < 300) || xhr.status === 0) {
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resolve(xhr, url);
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} else {
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reject(xhr, url);
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}
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}
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}.bind(this, section, xhr);
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xhr.open("GET", url, true);
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try {
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xhr.send();
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} catch (e) {
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console.warn(
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"Failed to get the Markdown file " +
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url +
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". Make sure that the presentation and the file are served by a HTTP server and the file can be found there. " +
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e
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);
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resolve(xhr, url);
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}
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});
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}
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/**
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* Check if a node value has the attributes pattern.
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* If yes, extract it and add that value as one or several attributes
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* to the target element.
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*
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* You need Cache Killer on Chrome to see the effect on any FOM transformation
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* directly on refresh (F5)
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* http://stackoverflow.com/questions/5690269/disabling-chrome-cache-for-website-development/7000899#answer-11786277
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*/
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function addAttributeInElement(node, elementTarget, separator) {
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var mardownClassesInElementsRegex = new RegExp(separator, "mg");
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var mardownClassRegex = new RegExp(
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'([^"= ]+?)="([^"]+?)"|(data-[^"= ]+?)(?=[" ])',
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"mg"
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);
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var nodeValue = node.nodeValue;
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var matches, matchesClass;
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if ((matches = mardownClassesInElementsRegex.exec(nodeValue))) {
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var classes = matches[1];
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nodeValue =
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nodeValue.substring(0, matches.index) +
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nodeValue.substring(mardownClassesInElementsRegex.lastIndex);
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node.nodeValue = nodeValue;
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while ((matchesClass = mardownClassRegex.exec(classes))) {
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if (matchesClass[2]) {
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elementTarget.setAttribute(matchesClass[1], matchesClass[2]);
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} else {
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elementTarget.setAttribute(matchesClass[3], "");
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}
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}
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return true;
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}
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return false;
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}
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/**
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* Add attributes to the parent element of a text node,
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* or the element of an attribute node.
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*/
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function addAttributes(
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section,
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element,
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previousElement,
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separatorElementAttributes,
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separatorSectionAttributes
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) {
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if (
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element != null &&
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element.childNodes != undefined &&
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element.childNodes.length > 0
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) {
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var previousParentElement = element;
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for (var i = 0; i < element.childNodes.length; i++) {
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var childElement = element.childNodes[i];
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if (i > 0) {
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var j = i - 1;
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while (j >= 0) {
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var aPreviousChildElement = element.childNodes[j];
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if (
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typeof aPreviousChildElement.setAttribute == "function" &&
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aPreviousChildElement.tagName != "BR"
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) {
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previousParentElement = aPreviousChildElement;
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break;
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}
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j = j - 1;
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}
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}
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var parentSection = section;
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if (childElement.nodeName == "section") {
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parentSection = childElement;
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previousParentElement = childElement;
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}
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if (
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typeof childElement.setAttribute == "function" ||
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childElement.nodeType == Node.COMMENT_NODE
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) {
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addAttributes(
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parentSection,
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childElement,
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previousParentElement,
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separatorElementAttributes,
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separatorSectionAttributes
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);
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}
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}
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}
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if (element.nodeType == Node.COMMENT_NODE) {
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if (
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addAttributeInElement(
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element,
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previousElement,
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separatorElementAttributes
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) == false
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) {
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addAttributeInElement(element, section, separatorSectionAttributes);
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}
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}
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}
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/**
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* Converts any current data-markdown slides in the
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* DOM to HTML.
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*/
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function convertSlides() {
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var sections = deck
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.getRevealElement()
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.querySelectorAll("[data-markdown]:not([data-markdown-parsed])");
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[].slice.call(sections).forEach(function (section) {
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section.setAttribute("data-markdown-parsed", true);
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var notes = section.querySelector("aside.notes");
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var markdown = getMarkdownFromSlide(section);
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section.innerHTML = marked(markdown);
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addAttributes(
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section,
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section,
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null,
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section.getAttribute("data-element-attributes") ||
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section.parentNode.getAttribute("data-element-attributes") ||
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DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR,
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section.getAttribute("data-attributes") ||
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section.parentNode.getAttribute("data-attributes") ||
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DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR
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);
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// If there were notes, we need to re-add them after
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// having overwritten the section's HTML
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if (notes) {
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section.appendChild(notes);
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}
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});
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return Promise.resolve();
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}
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function escapeForHTML(input) {
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return input.replace(/([&<>'"])/g, (char) => HTML_ESCAPE_MAP[char]);
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}
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return {
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id: "markdown",
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/**
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* Starts processing and converting Markdown within the
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* current reveal.js deck.
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*/
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init: function (reveal) {
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deck = reveal;
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let { renderer, animateLists, ...markedOptions } =
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deck.getConfig().markdown || {};
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if (!renderer) {
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renderer = new marked.Renderer();
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renderer.code = (code, language) => {
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// Off by default
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let lineNumbers = "";
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// Users can opt in to show line numbers and highlight
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// specific lines.
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// ```javascript [] show line numbers
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// ```javascript [1,4-8] highlights lines 1 and 4-8
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if (CODE_LINE_NUMBER_REGEX.test(language)) {
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lineNumbers = language.match(CODE_LINE_NUMBER_REGEX)[1].trim();
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lineNumbers = `data-line-numbers="${lineNumbers}"`;
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language = language.replace(CODE_LINE_NUMBER_REGEX, "").trim();
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}
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// Escape before this gets injected into the DOM to
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// avoid having the HTML parser alter our code before
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// highlight.js is able to read it
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code = escapeForHTML(code);
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return `<pre><code ${lineNumbers} class="${language}">${code}</code></pre>`;
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};
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}
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if (animateLists === true) {
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renderer.listitem = (text) => `<li class="fragment">${text}</li>`;
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}
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marked.setOptions({
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renderer,
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...markedOptions,
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});
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return processSlides(deck.getRevealElement()).then(convertSlides);
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},
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// TODO: Do these belong in the API?
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processSlides: processSlides,
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convertSlides: convertSlides,
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slidify: slidify,
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marked: marked,
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};
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};
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export default Plugin;
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