diff --git a/packages/nuxt/src/components/runtime/client-io-component.ts b/packages/nuxt/src/components/runtime/client-io-component.ts
index e8f07a47c7..081e2d82a7 100644
--- a/packages/nuxt/src/components/runtime/client-io-component.ts
+++ b/packages/nuxt/src/components/runtime/client-io-component.ts
@@ -3,7 +3,7 @@ import { defineComponent, onMounted, onUnmounted, ref } from 'vue'
 export default defineComponent({
   setup (props, { emit }) {
     const intersectionTarget = ref(null)
-    let observer = null
+    let observer: IntersectionObserver | null = null
 
     const intersectionCallback = (entries) => {
       entries.forEach((entry) => {