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Diffstat (limited to '2024-06-18-guix-social/reveal.js/plugin/markdown/plugin.js')
| -rwxr-xr-x | 2024-06-18-guix-social/reveal.js/plugin/markdown/plugin.js | 491 |
1 files changed, 491 insertions, 0 deletions
diff --git a/2024-06-18-guix-social/reveal.js/plugin/markdown/plugin.js b/2024-06-18-guix-social/reveal.js/plugin/markdown/plugin.js new file mode 100755 index 0000000..61de615 --- /dev/null +++ b/2024-06-18-guix-social/reveal.js/plugin/markdown/plugin.js @@ -0,0 +1,491 @@ +/*! + * 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 +// [<line numbers>] or [<offset>: <line numbers>] +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 <script> or <textarea data-template> wrapper + const template = section.querySelector( '[data-template]' ) || section.querySelector( 'script' ); + + // strip leading whitespace so it isn't evaluated as code + let text = ( template || section ).textContent; + + // restore script end tags + text = text.replace( new RegExp( SCRIPT_END_PLACEHOLDER, 'g' ), '</script>' ); + + 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] + '<aside class="notes">' + marked(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 ); + + 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 <section data-markdown> tags + for( let 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( 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 = '<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>'; + } + + ) ); + + } + 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 `<pre><code ${lineNumbers} class="${language}">${code}</code></pre>`; + + return `<pre><code ${lineNumbers} ${lineNumberOffset} class="${language}">${code}</code></pre>`; + }; + } + + if( animateLists === true ) { + renderer.listitem = text => `<li class="fragment">${text}</li>`; + } + + 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; |