/*! * The reveal.js markdown plugin. Handles parsing of * markdown inside of presentations as well as loading * of external markdown documents. */ import { marked } from 'marked'; const DEFAULT_SLIDE_SEPARATOR = '\r?\n---\r?\n', DEFAULT_VERTICAL_SEPARATOR = null, DEFAULT_NOTES_SEPARATOR = '^\s*notes?:', DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR = '\\\.element\\\s*?(.+?)$', DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR = '\\\.slide:\\\s*?(\\\S.+?)$'; const SCRIPT_END_PLACEHOLDER = '__SCRIPT_END__'; // match an optional line number offset and highlight line numbers // [] or [: ] const CODE_LINE_NUMBER_REGEX = /\[\s*((\d*):)?\s*([\s\d,|-]*)\]/; const HTML_ESCAPE_MAP = { '&': '&', '<': '<', '>': '>', '"': '"', "'": ''' }; const Plugin = () => { // The reveal.js instance this plugin is attached to let deck; /** * Retrieves the markdown contents of a slide section * element. Normalizes leading tabs/whitespace. */ function getMarkdownFromSlide( section ) { // look for a ' ); const leadingWs = text.match( /^\n?(\s*)/ )[1].length, leadingTabs = text.match( /^\n?(\t*)/ )[1].length; if( leadingTabs > 0 ) { text = text.replace( new RegExp('\\n?\\t{' + leadingTabs + '}(.*)','g'), function(m, p1) { return '\n' + p1 ; } ); } else if( leadingWs > 1 ) { text = text.replace( new RegExp('\\n? {' + leadingWs + '}(.*)', 'g'), function(m, p1) { return '\n' + p1 ; } ); } 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 ) { const attributes = section.attributes; const result = []; for( let i = 0, len = attributes.length; i < len; i++ ) { const name = attributes[i].name, 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 ) { const markdownConfig = deck?.getConfig?.().markdown; options = options || {}; options.separator = options.separator || markdownConfig?.separator || DEFAULT_SLIDE_SEPARATOR; options.verticalSeparator = options.verticalSeparator || markdownConfig?.verticalSeparator || DEFAULT_VERTICAL_SEPARATOR; options.notesSeparator = options.notesSeparator || markdownConfig?.notesSeparator || DEFAULT_NOTES_SEPARATOR; options.attributes = options.attributes || ''; return options; } /** * Helper function for constructing a markdown slide. */ function createMarkdownSlide( content, options ) { options = getSlidifyOptions( options ); const notesMatch = content.split( new RegExp( options.notesSeparator, 'mgi' ) ); if( notesMatch.length === 2 ) { content = notesMatch[0] + ''; } // prevent script end tags in the content from interfering // with parsing content = content.replace( /<\/script>/g, SCRIPT_END_PLACEHOLDER ); return ''; } /** * Parses a data string into multiple slides based * on the passed in separator arguments. */ function slidify( markdown, options ) { options = getSlidifyOptions( options ); const separatorRegex = new RegExp( options.separator + ( options.verticalSeparator ? '|' + options.verticalSeparator : '' ), 'mg' ), horizontalSeparatorRegex = new RegExp( options.separator ); let matches, lastIndex = 0, isHorizontal, wasHorizontal = true, content, sectionStack = []; // iterate until all blocks between separators are stacked up while( matches = separatorRegex.exec( markdown ) ) { const notes = 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 ) ); let markdownSections = ''; // flatten the hierarchical stack, and insert
tags for( let i = 0, len = sectionStack.length; i < len; i++ ) { // vertical if( sectionStack[i] instanceof Array ) { markdownSections += '
'; sectionStack[i].forEach( function( child ) { markdownSections += '
' + createMarkdownSlide( child, options ) + '
'; } ); markdownSections += '
'; } else { markdownSections += '
' + createMarkdownSlide( sectionStack[i], options ) + '
'; } } return markdownSections; } /** * Parses any current data-markdown slides, splits * multi-slide markdown into separate sections and * handles loading of external markdown. */ function processSlides( scope ) { return new Promise( function( resolve ) { const externalPromises = []; [].slice.call( scope.querySelectorAll( 'section[data-markdown]:not([data-markdown-parsed])') ).forEach( function( section, i ) { if( section.getAttribute( 'data-markdown' ).length ) { externalPromises.push( loadExternalMarkdown( section ).then( // Finished loading external file function( xhr, url ) { 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 ) }); }, // Failed to load markdown function( xhr, url ) { section.outerHTML = '
' + 'ERROR: The attempt to fetch ' + url + ' failed with HTTP status ' + xhr.status + '.' + 'Check your browser\'s JavaScript console for more details.' + '

Remember that you need to serve the presentation HTML from a HTTP server.

' + '
'; } ) ); } else { 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 ) }); } }); Promise.all( externalPromises ).then( resolve ); } ); } function loadExternalMarkdown( section ) { return new Promise( function( resolve, reject ) { const xhr = new XMLHttpRequest(), url = section.getAttribute( 'data-markdown' ); const 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( section, xhr ) { 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 ) { resolve( xhr, url ); } else { reject( xhr, url ); } } }.bind( this, section, xhr ); xhr.open( 'GET', url, true ); try { xhr.send(); } catch ( e ) { console.warn( '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 ); resolve( xhr, url ); } } ); } /** * Check if a node value has the attributes pattern. * If yes, extract it and add that value as one or several attributes * to the target 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 ) { const markdownClassesInElementsRegex = new RegExp( separator, 'mg' ); const markdownClassRegex = new RegExp( "([^\"= ]+?)=\"([^\"]+?)\"|(data-[^\"= ]+?)(?=[\" ])", 'mg' ); let nodeValue = node.nodeValue; let matches, matchesClass; if( matches = markdownClassesInElementsRegex.exec( nodeValue ) ) { const classes = matches[1]; nodeValue = nodeValue.substring( 0, matches.index ) + nodeValue.substring( markdownClassesInElementsRegex.lastIndex ); node.nodeValue = nodeValue; while( matchesClass = markdownClassRegex.exec( classes ) ) { if( matchesClass[2] ) { elementTarget.setAttribute( matchesClass[1], matchesClass[2] ); } else { elementTarget.setAttribute( matchesClass[3], "" ); } } 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 ) { let previousParentElement = element; for( let i = 0; i < element.childNodes.length; i++ ) { const childElement = element.childNodes[i]; if ( i > 0 ) { let j = i - 1; while ( j >= 0 ) { const aPreviousChildElement = element.childNodes[j]; if ( typeof aPreviousChildElement.setAttribute === 'function' && aPreviousChildElement.tagName !== "BR" ) { previousParentElement = aPreviousChildElement; break; } j = j - 1; } } let 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() { const sections = deck.getRevealElement().querySelectorAll( '[data-markdown]:not([data-markdown-parsed])'); [].slice.call( sections ).forEach( function( section ) { section.setAttribute( 'data-markdown-parsed', true ) const notes = section.querySelector( 'aside.notes' ); const markdown = getMarkdownFromSlide( section ); section.innerHTML = marked( markdown ); 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 ); } } ); return Promise.resolve(); } function escapeForHTML( input ) { return input.replace( /([&<>'"])/g, char => HTML_ESCAPE_MAP[char] ); } return { id: 'markdown', /** * Starts processing and converting Markdown within the * current reveal.js deck. */ init: function( reveal ) { deck = reveal; let { renderer, animateLists, ...markedOptions } = deck.getConfig().markdown || {}; if( !renderer ) { renderer = new marked.Renderer(); renderer.code = ( code, language ) => { // Off by default let lineNumberOffset = ''; let lineNumbers = ''; // Users can opt in to show line numbers and highlight // specific lines. // ```javascript [] show line numbers // ```javascript [1,4-8] highlights lines 1 and 4-8 // optional line number offset: // ```javascript [25: 1,4-8] start line numbering at 25, // highlights lines 1 (numbered as 25) and 4-8 (numbered as 28-32) if( CODE_LINE_NUMBER_REGEX.test( language ) ) { let lineNumberOffsetMatch = language.match( CODE_LINE_NUMBER_REGEX )[2]; if (lineNumberOffsetMatch){ lineNumberOffset = `data-ln-start-from="${lineNumberOffsetMatch.trim()}"`; } lineNumbers = language.match( CODE_LINE_NUMBER_REGEX )[3].trim(); lineNumbers = `data-line-numbers="${lineNumbers}"`; language = language.replace( CODE_LINE_NUMBER_REGEX, '' ).trim(); } // Escape before this gets injected into the DOM to // avoid having the HTML parser alter our code before // highlight.js is able to read it code = escapeForHTML( code ); // return `
${code}
`; return `
${code}
`; }; } if( animateLists === true ) { renderer.listitem = text => `
  • ${text}
  • `; } marked.setOptions( { renderer, ...markedOptions } ); return processSlides( deck.getRevealElement() ).then( convertSlides ); }, // TODO: Do these belong in the API? processSlides: processSlides, convertSlides: convertSlides, slidify: slidify, marked: marked } }; export default Plugin;