<p><b>@mmd-osm</b> commented on this pull request.</p>

<hr>

<p>In <a href="https://github.com/openstreetmap/openstreetmap-website/pull/2223#discussion_r300085505">app/views/api/map/index.xml.builder</a>:</p>
<pre style='color:#555'>> @@ -0,0 +1,8 @@
+xml.instruct!
+
+xml.osm(OSM::API.new.xml_root_attributes) do |osm|
+  osm << (render(:partial => "bounds", :object => @bounds) || "")
+  osm << (render(@nodes) || "")
+  osm << (render(@ways) || "")
+  osm << (render(@relations) || "")
</pre>
<p>That’s a logical or operator. If render returns nil, an empty string is added to the result as a fallback. See <a class="issue-link js-issue-link" data-error-text="Failed to load issue title" data-id="441428833" data-permission-text="Issue title is private" data-url="https://github.com/openstreetmap/openstreetmap-website/issues/2223" data-hovercard-type="pull_request" data-hovercard-url="/openstreetmap/openstreetmap-website/pull/2223/hovercard?comment_id=506019631&comment_type=issue_comment" href="https://github.com/openstreetmap/openstreetmap-website/pull/2223#issuecomment-506019631">#2223 (comment)</a></p>

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