diff --git a/src/node_file.cc b/src/node_file.cc
index 4e975530b2c63c..5abdc6a941c0d2 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -1832,8 +1832,8 @@ static void WriteBuffer(const FunctionCallbackInfo<Value>& args) {
   CHECK_LE(static_cast<uint64_t>(off_64), buffer_length);
   const size_t off = static_cast<size_t>(off_64);
 
-  CHECK(args[3]->IsInt32());
-  const size_t len = static_cast<size_t>(args[3].As<Int32>()->Value());
+  CHECK(IsSafeJsInt(args[3]));
+  const size_t len = static_cast<size_t>(args[3].As<Integer>()->Value());
   CHECK(Buffer::IsWithinBounds(off, len, buffer_length));
   CHECK_LE(len, buffer_length);
   CHECK_GE(off + len, off);