server-ts: Port services/export/md

src/services/export/md.ts

@@ -0,0 +1,19 @@
+"use strict";
+
+import TurndownService = require('turndown');
+import turndownPluginGfm = require('joplin-turndown-plugin-gfm');
+
+let instance: TurndownService | null = null;
+
+function toMarkdown(content: string) {
+    if (instance === null) {
+        instance = new TurndownService({ codeBlockStyle: 'fenced' });
+        instance.use(turndownPluginGfm.gfm);
+    }
+
+    return instance.turndown(content);
+}
+
+export = {
+    toMarkdown
+};