use GFM extensions for markdown export, closes #638

package-lock.json

@@ -1549,7 +1549,7 @@
     },
     "buf-compare": {
       "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/buf-compare/-/buf-compare-1.0.1.tgz",
+      "resolved": "http://registry.npmjs.org/buf-compare/-/buf-compare-1.0.1.tgz",
       "integrity": "sha1-/vKNqLgROgoNtEMLC2Rntpcws0o=",
       "dev": true
     },
@@ -4713,7 +4713,7 @@
         },
         "load-json-file": {
           "version": "2.0.0",
-          "resolved": "https://registry.npmjs.org/load-json-file/-/load-json-file-2.0.0.tgz",
+          "resolved": "http://registry.npmjs.org/load-json-file/-/load-json-file-2.0.0.tgz",
           "integrity": "sha1-eUfkIUmvgNaWy/eXvKq8/h/inKg=",
           "dev": true,
           "requires": {
@@ -13130,6 +13130,11 @@
         "jsdom": "^11.9.0"
       }
     },
+    "turndown-plugin-gfm": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/turndown-plugin-gfm/-/turndown-plugin-gfm-1.0.2.tgz",
+      "integrity": "sha512-vwz9tfvF7XN/jE0dGoBei3FXWuvll78ohzCZQuOb+ZjWrs3a0XhQVomJEb2Qh4VHTPNRO4GPZh0V7VRbiWwkRg=="
+    },
     "tweetnacl": {
       "version": "0.14.5",
       "resolved": "https://registry.npmjs.org/tweetnacl/-/tweetnacl-0.14.5.tgz",

package.json

@@ -73,6 +73,7 @@
     "string-similarity": "^3.0.0",
     "tar-stream": "2.1.0",
     "turndown": "5.0.3",
+    "turndown-plugin-gfm": "1.0.2",
     "unescape": "1.0.1",
     "ws": "7.1.2",
     "xml2js": "0.4.22"

src/services/export/md.js

@@ -0,0 +1,19 @@
+"use strict";
+
+const TurndownService = require('turndown');
+const turndownPluginGfm = require('turndown-plugin-gfm');
+
+let instance = null;
+
+function toMarkdown(content) {
+    if (instance === null) {
+        instance = new TurndownService();
+        instance.use(turndownPluginGfm.gfm);
+    }
+
+    return instance.turndown(content);
+}
+
+module.exports = {
+    toMarkdown
+};

src/services/export/single.js

@@ -1,9 +1,9 @@
 "use strict";
 
-const TurndownService = require('turndown');
 const mimeTypes = require('mime-types');
 const html = require('html');
 const utils = require('../utils');
+const mdService = require('./md');
 
 async function exportSingleNote(exportContext, branch, format, res) {
     const note = await branch.getNote();
@@ -31,8 +31,7 @@ async function exportSingleNote(exportContext, branch, format, res) {
             mime = 'text/html';
         }
         else if (format === 'markdown') {
-            const turndownService = new TurndownService();
-            payload = turndownService.turndown(content);
+            payload = mdService.toMarkdown(content);
             extension = 'md';
             mime = 'text/x-markdown'
         }

src/services/export/tar.js

@@ -5,7 +5,7 @@ const repository = require('../repository');
 const tar = require('tar-stream');
 const path = require('path');
 const mimeTypes = require('mime-types');
-const TurndownService = require('turndown');
+const mdService = require('./md');
 const packageInfo = require('../../../package.json');
 const utils = require('../utils');
 const protectedSessionService = require('../protected_session');
@@ -17,8 +17,6 @@ const sanitize = require("sanitize-filename");
  * @param {string} format - 'html' or 'markdown'
  */
 async function exportToTar(exportContext, branch, format, res) {
-    let turndownService = format === 'markdown' ? new TurndownService() : null;
-
     const pack = tar.pack();
 
     const noteIdToMeta = {};
@@ -232,7 +230,7 @@ ${content}
             return html.prettyPrint(content, {indent_size: 2});
         }
         else if (noteMeta.format === 'markdown') {
-            let markdownContent = turndownService.turndown(content);
+            let markdownContent = mdService.toMarkdown(content);
 
             if (markdownContent.trim().length > 0 && !markdownContent.startsWith("# ")) {
                 markdownContent = '# ' + title + "\r\n" + markdownContent;