From ef7783222dd48ffcab1acac0ba6df5a7272948be Mon Sep 17 00:00:00 2001
From: Zach Leatherman <zachleatherman@gmail.com>
Date: Wed, 29 Aug 2018 08:46:06 -0500
Subject: [PATCH] Adds a /tags/ to list all valid tags

---
 .eleventy.js        |  2 ++
 .eleventyignore     |  1 +
 _11ty/getTagList.js | 29 +++++++++++++++++++++++++++++
 package.json        |  2 +-
 tags-list.njk       | 10 ++++++++++
 tags.njk            |  3 ++-
 6 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 _11ty/getTagList.js
 create mode 100644 tags-list.njk

diff --git a/.eleventy.js b/.eleventy.js
index 55c32d2..b387b3c 100644
--- a/.eleventy.js
+++ b/.eleventy.js
@@ -19,6 +19,8 @@ module.exports = function(eleventyConfig) {
     });
   });
 
+  eleventyConfig.addCollection("tagList", require("./_11ty/getTagList"));
+
   eleventyConfig.addPassthroughCopy("img");
   eleventyConfig.addPassthroughCopy("css");
 
diff --git a/.eleventyignore b/.eleventyignore
index b43bf86..ec64229 100644
--- a/.eleventyignore
+++ b/.eleventyignore
@@ -1 +1,2 @@
 README.md
+_11ty/
diff --git a/_11ty/getTagList.js b/_11ty/getTagList.js
new file mode 100644
index 0000000..6b2882a
--- /dev/null
+++ b/_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);
+};
diff --git a/package.json b/package.json
index 7a7e81d..205e5ea 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
   },
   "homepage": "https://github.com/11ty/eleventy-base-blog#readme",
   "devDependencies": {
-    "@11ty/eleventy": "^0.4.0",
+    "@11ty/eleventy": "^0.5.3",
     "@11ty/eleventy-plugin-rss": "^1.0.2",
     "@11ty/eleventy-plugin-syntaxhighlight": "^1.0.5",
     "luxon": "^1.0.0",
diff --git a/tags-list.njk b/tags-list.njk
new file mode 100644
index 0000000..1e2fea4
--- /dev/null
+++ b/tags-list.njk
@@ -0,0 +1,10 @@
+---
+permalink: /tags/
+layout: layouts/home.njk
+---
+<h1>Tags</h1>
+
+{% for tag in collections.tagList %}
+  {% set tagUrl %}/tags/{{ tag }}/{% endset %}
+  <a href="{{ tagUrl | url }}" class="tag">{{ tag }}</a>
+{% endfor %}
diff --git a/tags.njk b/tags.njk
index 32cf598..cac955a 100644
--- a/tags.njk
+++ b/tags.njk
@@ -11,8 +11,9 @@ pagination:
 permalink: /tags/{{ tag }}/
 layout: layouts/home.njk
 ---
-
 <h1>Tagged “{{ tag }}”</h1>
 
 {% set postslist = collections[ tag ] %}
 {% include "postslist.njk" %}
+
+<p>See <a href="/tags/">all tags</a>.</p>