réalise/_static/plugin/markdown/plugin.js (view raw)
1/*!
2 * The reveal.js markdown plugin. Handles parsing of
3 * markdown inside of presentations as well as loading
4 * of external markdown documents.
5 */
6
7import { marked } from 'marked';
8
9const DEFAULT_SLIDE_SEPARATOR = '\r?\n---\r?\n',
10 DEFAULT_NOTES_SEPARATOR = 'notes?:',
11 DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR = '\\\.element\\\s*?(.+?)$',
12 DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR = '\\\.slide:\\\s*?(\\\S.+?)$';
13
14const SCRIPT_END_PLACEHOLDER = '__SCRIPT_END__';
15
16const CODE_LINE_NUMBER_REGEX = /\[([\s\d,|-]*)\]/;
17
18const HTML_ESCAPE_MAP = {
19 '&': '&',
20 '<': '<',
21 '>': '>',
22 '"': '"',
23 "'": '''
24};
25
26const Plugin = () => {
27
28 // The reveal.js instance this plugin is attached to
29 let deck;
30
31 /**
32 * Retrieves the markdown contents of a slide section
33 * element. Normalizes leading tabs/whitespace.
34 */
35 function getMarkdownFromSlide( section ) {
36
37 // look for a <script> or <textarea data-template> wrapper
38 var template = section.querySelector( '[data-template]' ) || section.querySelector( 'script' );
39
40 // strip leading whitespace so it isn't evaluated as code
41 var text = ( template || section ).textContent;
42
43 // restore script end tags
44 text = text.replace( new RegExp( SCRIPT_END_PLACEHOLDER, 'g' ), '</script>' );
45
46 var leadingWs = text.match( /^\n?(\s*)/ )[1].length,
47 leadingTabs = text.match( /^\n?(\t*)/ )[1].length;
48
49 if( leadingTabs > 0 ) {
50 text = text.replace( new RegExp('\\n?\\t{' + leadingTabs + '}(.*)','g'), function(m, p1) { return '\n' + p1 ; } );
51 }
52 else if( leadingWs > 1 ) {
53 text = text.replace( new RegExp('\\n? {' + leadingWs + '}(.*)', 'g'), function(m, p1) { return '\n' + p1 ; } );
54 }
55
56 return text;
57
58 }
59
60 /**
61 * Given a markdown slide section element, this will
62 * return all arguments that aren't related to markdown
63 * parsing. Used to forward any other user-defined arguments
64 * to the output markdown slide.
65 */
66 function getForwardedAttributes( section ) {
67
68 var attributes = section.attributes;
69 var result = [];
70
71 for( var i = 0, len = attributes.length; i < len; i++ ) {
72 var name = attributes[i].name,
73 value = attributes[i].value;
74
75 // disregard attributes that are used for markdown loading/parsing
76 if( /data\-(markdown|separator|vertical|notes)/gi.test( name ) ) continue;
77
78 if( value ) {
79 result.push( name + '="' + value + '"' );
80 }
81 else {
82 result.push( name );
83 }
84 }
85
86 return result.join( ' ' );
87
88 }
89
90 /**
91 * Inspects the given options and fills out default
92 * values for what's not defined.
93 */
94 function getSlidifyOptions( options ) {
95
96 options = options || {};
97 options.separator = options.separator || DEFAULT_SLIDE_SEPARATOR;
98 options.notesSeparator = options.notesSeparator || DEFAULT_NOTES_SEPARATOR;
99 options.attributes = options.attributes || '';
100
101 return options;
102
103 }
104
105 /**
106 * Helper function for constructing a markdown slide.
107 */
108 function createMarkdownSlide( content, options ) {
109
110 options = getSlidifyOptions( options );
111
112 var notesMatch = content.split( new RegExp( options.notesSeparator, 'mgi' ) );
113
114 if( notesMatch.length === 2 ) {
115 content = notesMatch[0] + '<aside class="notes">' + marked(notesMatch[1].trim()) + '</aside>';
116 }
117
118 // prevent script end tags in the content from interfering
119 // with parsing
120 content = content.replace( /<\/script>/g, SCRIPT_END_PLACEHOLDER );
121
122 return '<script type="text/template">' + content + '</script>';
123
124 }
125
126 /**
127 * Parses a data string into multiple slides based
128 * on the passed in separator arguments.
129 */
130 function slidify( markdown, options ) {
131
132 options = getSlidifyOptions( options );
133
134 var separatorRegex = new RegExp( options.separator + ( options.verticalSeparator ? '|' + options.verticalSeparator : '' ), 'mg' ),
135 horizontalSeparatorRegex = new RegExp( options.separator );
136
137 var matches,
138 lastIndex = 0,
139 isHorizontal,
140 wasHorizontal = true,
141 content,
142 sectionStack = [];
143
144 // iterate until all blocks between separators are stacked up
145 while( matches = separatorRegex.exec( markdown ) ) {
146 var notes = null;
147
148 // determine direction (horizontal by default)
149 isHorizontal = horizontalSeparatorRegex.test( matches[0] );
150
151 if( !isHorizontal && wasHorizontal ) {
152 // create vertical stack
153 sectionStack.push( [] );
154 }
155
156 // pluck slide content from markdown input
157 content = markdown.substring( lastIndex, matches.index );
158
159 if( isHorizontal && wasHorizontal ) {
160 // add to horizontal stack
161 sectionStack.push( content );
162 }
163 else {
164 // add to vertical stack
165 sectionStack[sectionStack.length-1].push( content );
166 }
167
168 lastIndex = separatorRegex.lastIndex;
169 wasHorizontal = isHorizontal;
170 }
171
172 // add the remaining slide
173 ( wasHorizontal ? sectionStack : sectionStack[sectionStack.length-1] ).push( markdown.substring( lastIndex ) );
174
175 var markdownSections = '';
176
177 // flatten the hierarchical stack, and insert <section data-markdown> tags
178 for( var i = 0, len = sectionStack.length; i < len; i++ ) {
179 // vertical
180 if( sectionStack[i] instanceof Array ) {
181 markdownSections += '<section '+ options.attributes +'>';
182
183 sectionStack[i].forEach( function( child ) {
184 markdownSections += '<section data-markdown>' + createMarkdownSlide( child, options ) + '</section>';
185 } );
186
187 markdownSections += '</section>';
188 }
189 else {
190 markdownSections += '<section '+ options.attributes +' data-markdown>' + createMarkdownSlide( sectionStack[i], options ) + '</section>';
191 }
192 }
193
194 return markdownSections;
195
196 }
197
198 /**
199 * Parses any current data-markdown slides, splits
200 * multi-slide markdown into separate sections and
201 * handles loading of external markdown.
202 */
203 function processSlides( scope ) {
204
205 return new Promise( function( resolve ) {
206
207 var externalPromises = [];
208
209 [].slice.call( scope.querySelectorAll( 'section[data-markdown]:not([data-markdown-parsed])') ).forEach( function( section, i ) {
210
211 if( section.getAttribute( 'data-markdown' ).length ) {
212
213 externalPromises.push( loadExternalMarkdown( section ).then(
214
215 // Finished loading external file
216 function( xhr, url ) {
217 section.outerHTML = slidify( xhr.responseText, {
218 separator: section.getAttribute( 'data-separator' ),
219 verticalSeparator: section.getAttribute( 'data-separator-vertical' ),
220 notesSeparator: section.getAttribute( 'data-separator-notes' ),
221 attributes: getForwardedAttributes( section )
222 });
223 },
224
225 // Failed to load markdown
226 function( xhr, url ) {
227 section.outerHTML = '<section data-state="alert">' +
228 'ERROR: The attempt to fetch ' + url + ' failed with HTTP status ' + xhr.status + '.' +
229 'Check your browser\'s JavaScript console for more details.' +
230 '<p>Remember that you need to serve the presentation HTML from a HTTP server.</p>' +
231 '</section>';
232 }
233
234 ) );
235
236 }
237 else {
238
239 section.outerHTML = slidify( getMarkdownFromSlide( section ), {
240 separator: section.getAttribute( 'data-separator' ),
241 verticalSeparator: section.getAttribute( 'data-separator-vertical' ),
242 notesSeparator: section.getAttribute( 'data-separator-notes' ),
243 attributes: getForwardedAttributes( section )
244 });
245
246 }
247
248 });
249
250 Promise.all( externalPromises ).then( resolve );
251
252 } );
253
254 }
255
256 function loadExternalMarkdown( section ) {
257
258 return new Promise( function( resolve, reject ) {
259
260 var xhr = new XMLHttpRequest(),
261 url = section.getAttribute( 'data-markdown' );
262
263 var datacharset = section.getAttribute( 'data-charset' );
264
265 // see https://developer.mozilla.org/en-US/docs/Web/API/element.getAttribute#Notes
266 if( datacharset != null && datacharset != '' ) {
267 xhr.overrideMimeType( 'text/html; charset=' + datacharset );
268 }
269
270 xhr.onreadystatechange = function( section, xhr ) {
271 if( xhr.readyState === 4 ) {
272 // file protocol yields status code 0 (useful for local debug, mobile applications etc.)
273 if ( ( xhr.status >= 200 && xhr.status < 300 ) || xhr.status === 0 ) {
274
275 resolve( xhr, url );
276
277 }
278 else {
279
280 reject( xhr, url );
281
282 }
283 }
284 }.bind( this, section, xhr );
285
286 xhr.open( 'GET', url, true );
287
288 try {
289 xhr.send();
290 }
291 catch ( e ) {
292 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 );
293 resolve( xhr, url );
294 }
295
296 } );
297
298 }
299
300 /**
301 * Check if a node value has the attributes pattern.
302 * If yes, extract it and add that value as one or several attributes
303 * to the target element.
304 *
305 * You need Cache Killer on Chrome to see the effect on any FOM transformation
306 * directly on refresh (F5)
307 * http://stackoverflow.com/questions/5690269/disabling-chrome-cache-for-website-development/7000899#answer-11786277
308 */
309 function addAttributeInElement( node, elementTarget, separator ) {
310
311 var mardownClassesInElementsRegex = new RegExp( separator, 'mg' );
312 var mardownClassRegex = new RegExp( "([^\"= ]+?)=\"([^\"]+?)\"|(data-[^\"= ]+?)(?=[\" ])", 'mg' );
313 var nodeValue = node.nodeValue;
314 var matches,
315 matchesClass;
316 if( matches = mardownClassesInElementsRegex.exec( nodeValue ) ) {
317
318 var classes = matches[1];
319 nodeValue = nodeValue.substring( 0, matches.index ) + nodeValue.substring( mardownClassesInElementsRegex.lastIndex );
320 node.nodeValue = nodeValue;
321 while( matchesClass = mardownClassRegex.exec( classes ) ) {
322 if( matchesClass[2] ) {
323 elementTarget.setAttribute( matchesClass[1], matchesClass[2] );
324 } else {
325 elementTarget.setAttribute( matchesClass[3], "" );
326 }
327 }
328 return true;
329 }
330 return false;
331 }
332
333 /**
334 * Add attributes to the parent element of a text node,
335 * or the element of an attribute node.
336 */
337 function addAttributes( section, element, previousElement, separatorElementAttributes, separatorSectionAttributes ) {
338
339 if ( element != null && element.childNodes != undefined && element.childNodes.length > 0 ) {
340 var previousParentElement = element;
341 for( var i = 0; i < element.childNodes.length; i++ ) {
342 var childElement = element.childNodes[i];
343 if ( i > 0 ) {
344 var j = i - 1;
345 while ( j >= 0 ) {
346 var aPreviousChildElement = element.childNodes[j];
347 if ( typeof aPreviousChildElement.setAttribute == 'function' && aPreviousChildElement.tagName != "BR" ) {
348 previousParentElement = aPreviousChildElement;
349 break;
350 }
351 j = j - 1;
352 }
353 }
354 var parentSection = section;
355 if( childElement.nodeName == "section" ) {
356 parentSection = childElement ;
357 previousParentElement = childElement ;
358 }
359 if ( typeof childElement.setAttribute == 'function' || childElement.nodeType == Node.COMMENT_NODE ) {
360 addAttributes( parentSection, childElement, previousParentElement, separatorElementAttributes, separatorSectionAttributes );
361 }
362 }
363 }
364
365 if ( element.nodeType == Node.COMMENT_NODE ) {
366 if ( addAttributeInElement( element, previousElement, separatorElementAttributes ) == false ) {
367 addAttributeInElement( element, section, separatorSectionAttributes );
368 }
369 }
370 }
371
372 /**
373 * Converts any current data-markdown slides in the
374 * DOM to HTML.
375 */
376 function convertSlides() {
377
378 var sections = deck.getRevealElement().querySelectorAll( '[data-markdown]:not([data-markdown-parsed])');
379
380 [].slice.call( sections ).forEach( function( section ) {
381
382 section.setAttribute( 'data-markdown-parsed', true )
383
384 var notes = section.querySelector( 'aside.notes' );
385 var markdown = getMarkdownFromSlide( section );
386
387 section.innerHTML = marked( markdown );
388 addAttributes( section, section, null, section.getAttribute( 'data-element-attributes' ) ||
389 section.parentNode.getAttribute( 'data-element-attributes' ) ||
390 DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR,
391 section.getAttribute( 'data-attributes' ) ||
392 section.parentNode.getAttribute( 'data-attributes' ) ||
393 DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR);
394
395 // If there were notes, we need to re-add them after
396 // having overwritten the section's HTML
397 if( notes ) {
398 section.appendChild( notes );
399 }
400
401 } );
402
403 return Promise.resolve();
404
405 }
406
407 function escapeForHTML( input ) {
408
409 return input.replace( /([&<>'"])/g, char => HTML_ESCAPE_MAP[char] );
410
411 }
412
413 return {
414 id: 'markdown',
415
416 /**
417 * Starts processing and converting Markdown within the
418 * current reveal.js deck.
419 */
420 init: function( reveal ) {
421
422 deck = reveal;
423
424 let { renderer, animateLists, ...markedOptions } = deck.getConfig().markdown || {};
425
426 if( !renderer ) {
427 renderer = new marked.Renderer();
428
429 renderer.code = ( code, language ) => {
430
431 // Off by default
432 let lineNumbers = '';
433
434 // Users can opt in to show line numbers and highlight
435 // specific lines.
436 // ```javascript [] show line numbers
437 // ```javascript [1,4-8] highlights lines 1 and 4-8
438 if( CODE_LINE_NUMBER_REGEX.test( language ) ) {
439 lineNumbers = language.match( CODE_LINE_NUMBER_REGEX )[1].trim();
440 lineNumbers = `data-line-numbers="${lineNumbers}"`;
441 language = language.replace( CODE_LINE_NUMBER_REGEX, '' ).trim();
442 }
443
444 // Escape before this gets injected into the DOM to
445 // avoid having the HTML parser alter our code before
446 // highlight.js is able to read it
447 code = escapeForHTML( code );
448
449 return `<pre><code ${lineNumbers} class="${language}">${code}</code></pre>`;
450 };
451 }
452
453 if( animateLists === true ) {
454 renderer.listitem = text => `<li class="fragment">${text}</li>`;
455 }
456
457 marked.setOptions( {
458 renderer,
459 ...markedOptions
460 } );
461
462 return processSlides( deck.getRevealElement() ).then( convertSlides );
463
464 },
465
466 // TODO: Do these belong in the API?
467 processSlides: processSlides,
468 convertSlides: convertSlides,
469 slidify: slidify,
470 marked: marked
471 }
472
473};
474
475export default Plugin;