diff --git a/.github/workflows/preview.yml b/.github/workflows/preview.yml
index b7abe729f..99b27967b 100644
--- a/.github/workflows/preview.yml
+++ b/.github/workflows/preview.yml
@@ -23,12 +23,20 @@ jobs:
         uses: ./.github/actions/execute-notebooks
 
       - name: Make BASE_URL
-        run: echo ${{ github.ref }} | sed "s/[^0-9]//g" | (v=$(cat); echo -e "BASE_URL=/pr-preview/pr-$v/" ) >> $GITHUB_ENV
+        uses: actions/github-script@v6
+        id: base-url
+        with:
+          script: |
+            const refName = "${{ github.ref_name }}"; // PR_NUMBER/merge
+            const prNumber = refName.slice(0, refName.length - 6);
+            const baseUrl = `/pr-preview/pr-${prNumber}/`;
+            return baseUrl;
+          result-encoding: string
 
       - name: Build
         uses: ./.github/actions/build
         with:
-          base-url: $BASE_URL
+          base-url: ${{ steps.base-url.outputs.result }}
 
       - name: Deploy preview
         uses: rossjrw/pr-preview-action@v1
diff --git a/docusaurus.config.js b/docusaurus.config.js
index 0e3bc81ab..88e1f2408 100644
--- a/docusaurus.config.js
+++ b/docusaurus.config.js
@@ -13,7 +13,7 @@ const config = {
   title: "Introduction to Algorithms",
   // tagline: '',
   url: "https://sikepuri-algorithm.github.io",
-  baseUrl: process.env.NODE_ENV ? "/" : process.env.BASE_URL,
+  baseUrl: process.env.NODE_ENV === "development" ? "/" : process.env.BASE_URL,
   onBrokenLinks: "throw",
   onBrokenMarkdownLinks: "warn",
   favicon: "img/favicon.ico",