Add more tag-related functions

index.js

@@ -287,7 +287,7 @@ async function getCategories(db) {
   return cats2
 }
 
-async function getTagCloud(db, limit) {
+async function getTagCloud(db, limit, offset=0) {
   const tags = db.prepare(`
     SELECT count(t.id) as c, t.name
     FROM article__tag a_t
@@ -296,7 +296,8 @@ async function getTagCloud(db, limit) {
     GROUP BY t.id
     ORDER BY c DESC
     LIMIT @limit
-  `).all({ limit })
+    OFFSET @offset
+  `).all({ limit, offset })
   return tags
 }
 
@@ -444,5 +445,8 @@ module.exports = {
   getArticleCounts,
   getArticlesByYearMonth,
   getArticlesByCategory,
-  countArticlesByCategory
+  countArticlesByCategory,
+  getArticlesByTag,
+  countArticlesByTag,
+  countTags
 }