Adds a /tags/ to list all valid tags

_11ty/getTagList.js

@@ -0,0 +1,29 @@
+module.exports = function(collection) {
+  let tagList = {};
+  collection.getAllSorted().forEach(function(item) {
+    if( "tags" in item.data ) {
+      let tags = item.data.tags;
+      if( typeof tags === "string" ) {
+        tags = [tags];
+      }
+
+      tags.filter(function(item) {
+        switch(item) {
+          // this list should match the `filter` list in tags.njk
+          case "all":
+          case "nav":
+          case "post":
+          case "posts":
+            return false;
+        }
+
+        return true;
+      }).forEach(function(tag) {
+        tagList[tag] = true;
+      });
+    }
+  });
+
+  // returning an array in addCollection works in Eleventy 0.5.3
+  return Object.keys(tagList);
+};