@@ -1,7 +1,7 @@
 # Copyright 2013 Lovell Fuller and others.
 # SPDX-License-Identifier: Apache-2.0
 
-{
+{ # noqa: B018
   'variables': {
     'vips_version': '<!(node -p "require(\'../dist/libvips.cjs\').minimumLibvipsVersion")',
     'platform_and_arch': '<!(node -p "require(\'../dist/libvips.cjs\').buildPlatformArch()")',
 
@@ -56,9 +56,9 @@ class PipelineWorker : public Napi::AsyncWorker {
           hasAlpha |= image.has_alpha();
         }
         if (hasAlpha) {
-          for (auto &image : images) {
-            if (!image.has_alpha()) {
-              image = sharp::EnsureAlpha(image, 1);
+          for (size_t i = 0; i < images.size(); i++) {
+            if (!images[i].has_alpha()) {
+              images[i] = sharp::EnsureAlpha(images[i], 1);
             }
           }
         } else {
 
@@ -133,7 +133,7 @@ Napi::Value format(const Napi::CallbackInfo& info) {
     input.Set("file", hasInputFile);
     input.Set("buffer", hasInputBuffer);
     input.Set("stream", hasInputBuffer);
-    if (hasInputFile) {
+    if (oc) {
       const VipsForeignClass *fc = VIPS_FOREIGN_CLASS(oc);
       if (fc->suffs) {
         Napi::Array fileSuffix = Napi::Array::New(env);
Original file line number	Diff line number	Diff line change
`@@ -56,9 +56,9 @@ class PipelineWorker : public Napi::AsyncWorker {`
`56`	`56`	`hasAlpha \|= image.has_alpha();`
`57`	`57`	`}`
`58`	`58`	`if (hasAlpha) {`
`59`		`- for (auto &image : images) {`
`60`		`- if (!image.has_alpha()) {`
`61`		`- image = sharp::EnsureAlpha(image, 1);`
	`59`	`+ for (size_t i = 0; i < images.size(); i++) {`
	`60`	`+ if (!images[i].has_alpha()) {`
	`61`	`+ images[i] = sharp::EnsureAlpha(images[i], 1);`
`62`	`62`	`}`
`63`	`63`	`}`
`64`	`64`	`} else {`