diff --git a/lib/browser/api/web-contents.ts b/lib/browser/api/web-contents.ts
index d97e86215dfce..cba02f7c849d0 100644
--- a/lib/browser/api/web-contents.ts
+++ b/lib/browser/api/web-contents.ts
@@ -668,7 +668,7 @@ WebContents.prototype._init = function () {
         disposition
       };
 
-      let result;
+      let result: ReturnType<typeof this._callWindowOpenHandler>;
       try {
         result = this._callWindowOpenHandler(event, details);
       } catch (err) {
@@ -707,7 +707,7 @@ WebContents.prototype._init = function () {
         postBody
       };
 
-      let result;
+      let result: ReturnType<typeof this._callWindowOpenHandler>;
       try {
         result = this._callWindowOpenHandler(event, details);
       } catch (err) {