feat: Initial clean release of CHM

packages/app-mobile/contentScripts/richTextEditorBundle/contentScript/convertHtmlToMarkdown.ts

@@ -0,0 +1,33 @@
+const TurndownService = require('@joplin/turndown');
+const turndownPluginGfm = require('@joplin/turndown-plugin-gfm').gfm;
+
+// Avoid using @joplin/lib/HtmlToMd here. HtmlToMd may cause several megabytes
+// of additional JavaScript and supporting data to be included.
+
+const convertHtmlToMarkdown = (html: string|HTMLElement) => {
+	const turndownOpts = {
+		headingStyle: 'atx',
+		codeBlockStyle: 'fenced',
+		preserveImageTagsWithSize: true,
+		preserveNestedTables: true,
+		preserveTableStyles: true,
+		preserveColorStyles: true,
+		bulletListMarker: '-',
+		emDelimiter: '*',
+		strongDelimiter: '**',
+		allowResourcePlaceholders: true,
+
+		// If soft-breaks are enabled, lines need to end with two or more spaces for
+		// trailing <br/>s to render. See
+		// https://github.com/laurent22/joplin/issues/8430
+		br: '  ',
+	};
+	const turndown = new TurndownService(turndownOpts);
+	turndown.use(turndownPluginGfm);
+	turndown.remove('script');
+	turndown.remove('style');
+	const md = turndown.turndown(html);
+	return md;
+};
+
+export default convertHtmlToMarkdown;