add slide separator in case no separator is provided and heading indi…

…cates the new slide

plugin/awesoMD/plugin.js

@@ -108,6 +108,7 @@ const Plugin = () => {
 		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.separateByHeading = options.separateByHeading || markdownConfig?.separateByHeading || false;
 		options.attributes = options.attributes || '';
 
 		return options;
@@ -146,7 +147,13 @@ const Plugin = () => {
 	 */
 	function slidify( markdown, options ) {
 
-		options = getSlidifyOptions( options );
+		options = getSlidifyOptions( options )
+
+		// add slide separator in the case heading indicates the new slide
+		if (options.separateByHeading) {
+			options['slideSeparator'] = '---'
+			markdown = addSlideSeparator(markdown, options)
+		}
 
 		const separatorRegex = new RegExp( options.separator + ( options.verticalSeparator ? '|' + options.verticalSeparator : '' ), 'mg' ),
 			horizontalSeparatorRegex = new RegExp( options.separator );
@@ -243,6 +250,7 @@ const Plugin = () => {
 								separator: section.getAttribute( 'data-separator' ),
 								verticalSeparator: section.getAttribute( 'data-separator-vertical' ),
 								notesSeparator: section.getAttribute( 'data-separator-notes' ),
+								separateByHeading: section.hasAttribute('data-separator-by-heading'),
 								attributes: getForwardedAttributes( section )
 							});
 						},
@@ -265,6 +273,7 @@ const Plugin = () => {
 						separator: section.getAttribute( 'data-separator' ),
 						verticalSeparator: section.getAttribute( 'data-separator-vertical' ),
 						notesSeparator: section.getAttribute( 'data-separator-notes' ),
+						separateByHeading: section.hasAttribute('data-separator-by-heading'),
 						attributes: getForwardedAttributes( section )
 					});
 
@@ -458,6 +467,33 @@ const Plugin = () => {
 		return [content, options];
 	}
 
+	/**
+	 * Add slide separator in case where the heading indicates the start of new slide
+	 *
+	 * Returns the updated markdown file with added slide separator above every slide headings
+	 */
+	function addSlideSeparator(markdown, options) {
+		const lines = markdown.split('\n')
+		const result = []
+		let firstHeadingProcessingDone = false
+
+		lines.forEach((line, index) => {
+			if (line.match(/^#{1,6}\s+/)) {
+				if (!firstHeadingProcessingDone) {
+					firstHeadingProcessingDone = true
+				} else {
+					const previousLine = lines[index - 1] || ''
+					if (previousLine !== options.slideSeparator) {
+						result.push(options.slideSeparator)
+					}
+				}
+			}
+			result.push(line)
+		})
+		markdown = result.join('\n')
+		return markdown
+	}
+
 	/**
 	 * Separates the inline metadata and content for slide having inline metadata in yaml block as
 	 *
@@ -525,18 +561,22 @@ const Plugin = () => {
 		const newMetadata = headingWithMetadataRegex.test(markdown)
 		yamlRegex.lastIndex = 0
 
-		switch (true) {
-			case newMetadata:
-				[markdown, options] = extractInlineMetadata(markdown, options)
-				break
-			case yamlMetadata:
-				[markdown, options] = extractYAMLMetadata(markdown, options)
-				break
-			default:
-				if (options.metadata) {
-					options.attributes = 'class=' + (options.metadata.slide || '')
-				}
-				break
+		if (options.separateByHeading) {
+			[markdown, options] = extractInlineMetadata(markdown, options)
+		} else {
+			switch (true) {
+				case newMetadata:
+					[markdown, options] = extractInlineMetadata(markdown, options)
+					break
+				case yamlMetadata:
+					[markdown, options] = extractYAMLMetadata(markdown, options)
+					break
+				default:
+					if (options.metadata) {
+						options.attributes = 'class=' + (options.metadata.slide || '')
+					}
+					break
+			}
 		}
 
 		return [markdown, options]