Fix deployment and count articles

serverless.yml

@@ -2,7 +2,7 @@ service: realworld
 
 provider:
   name: aws
-  runtime: nodejs8.10
+  runtime: nodejs14.x
   region: us-east-1
   environment:
     DYNAMODB_NAMESPACE: ${opt:stage, "dev"}

src/Article.js

@@ -268,7 +268,8 @@ module.exports = {
     }
     return Util.envelop({
       articles: await queryEnoughArticles(queryParams, authenticatedUser,
-        limit, offset)
+        limit, offset),
+      articlesCount: await countArticles(queryParams, authenticatedUser)
     });
   },
 
@@ -317,6 +318,7 @@ module.exports = {
     return Util.envelop({
       articles: await queryEnoughArticles(queryParams, authenticatedUser,
         limit, offset),
+      articlesCount: await countArticles(queryParams, authenticatedUser)
     });
   },
 
@@ -379,6 +381,20 @@ async function queryEnoughArticles(queryParams, authenticatedUser,
   return articles;
 }
 
+/**
+ * Given queryParams, return the number of articles that match.
+ */
+async function countArticles(queryParams, authenticatedUser,
+                                   limit, offset) {
+
+  const countQueryParams = Object.assign({}, queryParams, { Select: "COUNT" })
+
+  const queryResult = await Util.DocumentClient.query(countQueryParams)
+      .promise();
+
+  return queryResult.Count;
+}
+
 /**
  * Given an article retrieved from table,
  * decorate it with extra information like author, favorite, following etc.