diff --git a/src/types.ts b/src/types.ts
index 26beaba2..22446712 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -58,9 +58,11 @@ interface PerformanceEntryMap {
 
 // Update built-in types to be more accurate.
 declare global {
-  // https://wicg.github.io/nav-speculation/prerendering.html#document-prerendering
   interface Document {
-    prerendering?: boolean
+    // https://wicg.github.io/nav-speculation/prerendering.html#document-prerendering
+    prerendering?: boolean;
+    // https://github.com/WICG/page-lifecycle/blob/main/README.md
+    wasDiscarded?: boolean;
   }
 
   interface Performance {
diff --git a/src/types/base.ts b/src/types/base.ts
index 811e628e..1d2d0a6a 100644
--- a/src/types/base.ts
+++ b/src/types/base.ts
@@ -105,12 +105,3 @@ export interface ReportOpts {
  *   loading. This is equivalent to the corresponding `readyState` value.
  */
 export type LoadState = 'loading' | 'dom-interactive' | 'dom-content-loaded' | 'complete';
-
-/**
- * Extend the document with the new wasDiscarded boolean which is not supported
- * in typescript yet
- * https://github.com/WICG/page-lifecycle/blob/main/README.md
- */ 
-declare global {
-  interface Document { wasDiscarded?: boolean; }
-}
diff --git a/test/views/layout.njk b/test/views/layout.njk
index c3a3a9b4..9136e6f2 100644
--- a/test/views/layout.njk
+++ b/test/views/layout.njk
@@ -105,7 +105,6 @@
        */
       self.__stubWasDiscarded = () => {
         return new Promise((resolve) => {
-          const navEntry = performance.getEntriesByType('navigation')[0];
           // Only stub if the page isn't actually discarded.
           if (!document.wasDiscarded) {
             Object.defineProperty(document, 'wasDiscarded', {