From 519fca2e32d5cdd8511c0b6c8f0af508977d8636 Mon Sep 17 00:00:00 2001
From: Jesse Ashmore <29103230+JeeZeh@users.noreply.github.com>
Date: Mon, 10 Aug 2020 20:47:36 +0100
Subject: [PATCH] Open external links in OSM notes in a new tab

---
 modules/ui/note_comments.js | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/modules/ui/note_comments.js b/modules/ui/note_comments.js
index 4ace9a2cb..81bafb6b1 100644
--- a/modules/ui/note_comments.js
+++ b/modules/ui/note_comments.js
@@ -68,7 +68,12 @@ export function uiNoteComments() {
         mainEnter
             .append('div')
             .attr('class', 'comment-text')
-            .html(function(d) { return d.html; });
+            .html(function(d) { return d.html; })
+            .selectAll('a')
+                .filter(isExternalLink)
+                .attr('rel', 'noopener')
+                .attr('rel', 'nofollow')
+                .attr('target', '_blank');
 
         comments
             .call(replaceAvatars);
@@ -110,6 +115,22 @@ export function uiNoteComments() {
     }
 
 
+    // A quick test for external links. 'this' is the node passed in by selection.filter()
+    function isExternalLink() {
+        try {
+            // Possibly more domains to be added
+            const internalDomains = ['.openstreetmap.org', '.osm.org']; 
+            const hostname = new URL(this.href).hostname;
+
+            // If the link's hostname comprises any internalDomains, return false
+            return internalDomains.findIndex((d) => hostname.includes(d)) === -1; 
+        } catch (error) {
+            // If anything goes wrong, bail and assume not external (original behaviour)
+            return false;
+        }   
+    }
+
+
     noteComments.note = function(val) {
         if (!arguments.length) return _note;
         _note = val;