diff --git a/.vite/build.ts b/.vite/build.ts
index a03bdeec2..b3e5efb45 100644
--- a/.vite/build.ts
+++ b/.vite/build.ts
@@ -89,6 +89,10 @@ export const getBuildConfig = ({ minify, core, watch, entryName }: BuildOptions)
       }),
       ...visualizerOptions(packageName, core),
     ],
+    define: {
+      // Needs to be string
+      includeLargeDiagrams: 'true',
+    },
   };
 
   if (watch && config.build) {
diff --git a/packages/mermaid/src/types.d.ts b/packages/mermaid/src/types.d.ts
index 4f52a09df..2a0cf2d78 100644
--- a/packages/mermaid/src/types.d.ts
+++ b/packages/mermaid/src/types.d.ts
@@ -1 +1 @@
-declare let includeLargeDiagrams: boolean;
+declare const includeLargeDiagrams: boolean;
diff --git a/vite.config.ts b/vite.config.ts
index 080ff981f..d99f0d3ed 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -33,4 +33,8 @@ export default defineConfig({
       esmExternals: true,
     },
   },
+  define: {
+    // Needs to be string
+    includeLargeDiagrams: 'true',
+  },
 });