diff --git a/nix-js/runtime-ts/src/helpers.ts b/nix-js/runtime-ts/src/helpers.ts
index c48e31e..3c5689c 100644
--- a/nix-js/runtime-ts/src/helpers.ts
+++ b/nix-js/runtime-ts/src/helpers.ts
@@ -265,10 +265,11 @@ function selectWithDefault_impl(obj: NixValue, attrpath: NixValue[], default_val
 }
 
 export const hasAttr = (obj: NixValue, attrpath: NixValue[]): NixBool => {
-  if (!isAttrs(obj)) {
+  const forced = force(obj);
+  if (!isAttrs(forced)) {
     return false;
   }
-  let attrs = obj;
+  let attrs = forced;
 
   for (const attr of attrpath.slice(0, -1)) {
     const cur = force(attrs[forceString(attr)]);