diff --git a/.github/workflows/check.yaml b/.github/workflows/check.yaml
index 7dbf529..b877a6b 100644
--- a/.github/workflows/check.yaml
+++ b/.github/workflows/check.yaml
@@ -21,11 +21,14 @@ jobs:
           node-version-file: '.node-version'
           cache: 'pnpm'
 
-      - name: Install dependencies
-        run: make install
+      - name: Install dependencies & build application
+        run: make
 
       - name: Lint & format
         run: make lint
 
       - name: Run tests
         run: make test
+
+      - name: Confirm no error
+        run: make version
diff --git a/Makefile b/Makefile
index 0ee651b..71b5d83 100644
--- a/Makefile
+++ b/Makefile
@@ -29,3 +29,6 @@ lint:
 
 format:
 	pnpm format
+
+version:
+	pnpm exec node $(BUILD_DIR)/index.js --version
diff --git a/src/cost.ts b/src/cost.ts
index 9046427..bb70440 100644
--- a/src/cost.ts
+++ b/src/cost.ts
@@ -1,7 +1,7 @@
 import AWS from 'aws-sdk';
 import dayjs from 'dayjs';
-import isSameOrAfter from 'dayjs/plugin/isSameOrAfter';
-import isSameOrBefore from 'dayjs/plugin/isSameOrBefore';
+import isSameOrAfter from 'dayjs/plugin/isSameOrAfter.js';
+import isSameOrBefore from 'dayjs/plugin/isSameOrBefore.js';
 dayjs.extend(isSameOrAfter);
 dayjs.extend(isSameOrBefore);
 import { AWSConfig } from './config';