File size: 13,819 Bytes
b0d1496
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
/*!
 * 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_NOTES_SEPARATOR = 'notes?:',
	  DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR = '\\\.element\\\s*?(.+?)$',
	  DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR = '\\\.slide:\\\s*?(\\\S.+?)$';

const SCRIPT_END_PLACEHOLDER = '__SCRIPT_END__';

const CODE_LINE_NUMBER_REGEX = /\[([\s\d,|-]*)\]/;

const HTML_ESCAPE_MAP = {
  '&': '&',
  '<': '&lt;',
  '>': '&gt;',
  '"': '&quot;',
  "'": '&#39;'
};

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
		var template = section.querySelector( '[data-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,
			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,
				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">' + 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 );

		var separatorRegex = new RegExp( options.separator + ( options.verticalSeparator ? '|' + options.verticalSeparator : '' ), 'mg' ),
			horizontalSeparatorRegex = new RegExp( options.separator );

		var matches,
			lastIndex = 0,
			isHorizontal,
			wasHorizontal = true,
			content,
			sectionStack = [];

		// iterate until all blocks between separators are stacked up
		while( matches = separatorRegex.exec( markdown ) ) {
			var 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 ) );

		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( scope ) {

		return new Promise( function( resolve ) {

			var 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 ) {

			var xhr = new XMLHttpRequest(),
				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( 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 ) {

		var mardownClassesInElementsRegex = new RegExp( separator, 'mg' );
		var mardownClassRegex = new RegExp( "([^\"= ]+?)=\"([^\"]+?)\"|(data-[^\"= ]+?)(?=[\" ])", 'mg' );
		var nodeValue = node.nodeValue;
		var matches,
			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 ) ) {
				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 ) {
			var previousParentElement = element;
			for( var i = 0; i < element.childNodes.length; i++ ) {
				var childElement = element.childNodes[i];
				if ( i > 0 ) {
					var 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 = deck.getRevealElement().querySelectorAll( '[data-markdown]:not([data-markdown-parsed])');

		[].slice.call( sections ).forEach( function( section ) {

			section.setAttribute( 'data-markdown-parsed', true )

			var notes = section.querySelector( 'aside.notes' );
			var 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 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
					if( CODE_LINE_NUMBER_REGEX.test( language ) ) {
						lineNumbers = language.match( CODE_LINE_NUMBER_REGEX )[1].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>`;
				};
			}

			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;