diff --git a/lib/www/server/lib/render.js b/lib/www/server/lib/render.js
index 95dbd57..9e94db7 100644
--- a/lib/www/server/lib/render.js
+++ b/lib/www/server/lib/render.js
@@ -29,6 +29,10 @@ function njkCollect (entries, key, collectables) {
 	return out;
 }
 
+function njkUnique (entries) {
+	return entries.filter((element, index, array) => array.indexOf(element) === index);
+}
+
 function njkPadStart (str, len, chr) {
 	return String(str).padStart(len, chr);
 }
@@ -58,6 +62,7 @@ async function render (data, template) {
 	
 	const nenv = nunjucks.configure(Path.dirname(template), {autoescape: false, lstripBlocks: false, trimBlocks: false});
 	nenv.addFilter('find', njkFind);
+	nenv.addFilter('unique', njkUnique);
 	nenv.addFilter('collect', njkCollect);
 	nenv.addFilter('padStart', njkPadStart);
 	nenv.addFilter('timestamp', njkTimestamp);