diff --git a/package.json b/package.json
index 3f4beae4..f705e949 100644
--- a/package.json
+++ b/package.json
@@ -131,7 +131,7 @@
   "dependencies": {
     "color": "^4.2.3",
     "detect-libc": "^2.0.1",
-    "node-addon-api": "5.0.0",
+    "node-addon-api": "^5.1.0",
     "prebuild-install": "^7.1.1",
     "semver": "^7.3.8",
     "simple-get": "^4.0.1",
diff --git a/src/common.cc b/src/common.cc
index 6c47cc17..9038de2e 100644
--- a/src/common.cc
+++ b/src/common.cc
@@ -79,7 +79,9 @@ namespace sharp {
   Napi::Buffer<char> NewOrCopyBuffer(Napi::Env env, char* data, size_t len) {
     try {
       return Napi::Buffer<char>::New(env, data, len, FreeCallback);
-    } catch (Napi::Error const &err) {}
+    } catch (Napi::Error const &err) {
+      static_cast<void>(err);
+    }
     Napi::Buffer<char> buf = Napi::Buffer<char>::Copy(env, data, len);
     FreeCallback(nullptr, data);
     return buf;
diff --git a/src/metadata.cc b/src/metadata.cc
index 773e5bd1..cb69b034 100644
--- a/src/metadata.cc
+++ b/src/metadata.cc
@@ -276,7 +276,7 @@ class MetadataWorker : public Napi::AsyncWorker {
 Napi::Value metadata(const Napi::CallbackInfo& info) {
   // V8 objects are converted to non-V8 types held in the baton struct
   MetadataBaton *baton = new MetadataBaton;
-  Napi::Object options = info[0].As<Napi::Object>();
+  Napi::Object options = info[size_t(0)].As<Napi::Object>();
 
   // Input
   baton->input = sharp::CreateInputDescriptor(options.Get("input").As<Napi::Object>());
@@ -285,7 +285,7 @@ Napi::Value metadata(const Napi::CallbackInfo& info) {
   Napi::Function debuglog = options.Get("debuglog").As<Napi::Function>();
 
   // Join queue for worker thread
-  Napi::Function callback = info[1].As<Napi::Function>();
+  Napi::Function callback = info[size_t(1)].As<Napi::Function>();
   MetadataWorker *worker = new MetadataWorker(callback, baton, debuglog);
   worker->Receiver().Set("options", options);
   worker->Queue();
diff --git a/src/pipeline.cc b/src/pipeline.cc
index 93d93518..01030061 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -1387,7 +1387,7 @@ class PipelineWorker : public Napi::AsyncWorker {
 Napi::Value pipeline(const Napi::CallbackInfo& info) {
   // V8 objects are converted to non-V8 types held in the baton struct
   PipelineBaton *baton = new PipelineBaton;
-  Napi::Object options = info[0].As<Napi::Object>();
+  Napi::Object options = info[size_t(0)].As<Napi::Object>();
 
   // Input
   baton->input = sharp::CreateInputDescriptor(options.Get("input").As<Napi::Object>());
@@ -1661,7 +1661,7 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   Napi::Function queueListener = options.Get("queueListener").As<Napi::Function>();
 
   // Join queue for worker thread
-  Napi::Function callback = info[1].As<Napi::Function>();
+  Napi::Function callback = info[size_t(1)].As<Napi::Function>();
   PipelineWorker *worker = new PipelineWorker(callback, baton, debuglog, queueListener);
   worker->Receiver().Set("options", options);
   worker->Queue();
diff --git a/src/stats.cc b/src/stats.cc
index 5a6a3172..8a0ec7a2 100644
--- a/src/stats.cc
+++ b/src/stats.cc
@@ -172,7 +172,7 @@ class StatsWorker : public Napi::AsyncWorker {
 Napi::Value stats(const Napi::CallbackInfo& info) {
   // V8 objects are converted to non-V8 types held in the baton struct
   StatsBaton *baton = new StatsBaton;
-  Napi::Object options = info[0].As<Napi::Object>();
+  Napi::Object options = info[size_t(0)].As<Napi::Object>();
 
   // Input
   baton->input = sharp::CreateInputDescriptor(options.Get("input").As<Napi::Object>());
@@ -182,7 +182,7 @@ Napi::Value stats(const Napi::CallbackInfo& info) {
   Napi::Function debuglog = options.Get("debuglog").As<Napi::Function>();
 
   // Join queue for worker thread
-  Napi::Function callback = info[1].As<Napi::Function>();
+  Napi::Function callback = info[size_t(1)].As<Napi::Function>();
   StatsWorker *worker = new StatsWorker(callback, baton, debuglog);
   worker->Receiver().Set("options", options);
   worker->Queue();
diff --git a/src/utilities.cc b/src/utilities.cc
index da638289..ec2eb931 100644
--- a/src/utilities.cc
+++ b/src/utilities.cc
@@ -30,16 +30,16 @@ Napi::Value cache(const Napi::CallbackInfo& info) {
   Napi::Env env = info.Env();
 
   // Set memory limit
-  if (info[0].IsNumber()) {
-    vips_cache_set_max_mem(info[0].As<Napi::Number>().Int32Value() * 1048576);
+  if (info[size_t(0)].IsNumber()) {
+    vips_cache_set_max_mem(info[size_t(0)].As<Napi::Number>().Int32Value() * 1048576);
   }
   // Set file limit
-  if (info[1].IsNumber()) {
-    vips_cache_set_max_files(info[1].As<Napi::Number>().Int32Value());
+  if (info[size_t(1)].IsNumber()) {
+    vips_cache_set_max_files(info[size_t(1)].As<Napi::Number>().Int32Value());
   }
   // Set items limit
-  if (info[2].IsNumber()) {
-    vips_cache_set_max(info[2].As<Napi::Number>().Int32Value());
+  if (info[size_t(2)].IsNumber()) {
+    vips_cache_set_max(info[size_t(2)].As<Napi::Number>().Int32Value());
   }
 
   // Get memory stats
@@ -69,8 +69,8 @@ Napi::Value cache(const Napi::CallbackInfo& info) {
 */
 Napi::Value concurrency(const Napi::CallbackInfo& info) {
   // Set concurrency
-  if (info[0].IsNumber()) {
-    vips_concurrency_set(info[0].As<Napi::Number>().Int32Value());
+  if (info[size_t(0)].IsNumber()) {
+    vips_concurrency_set(info[size_t(0)].As<Napi::Number>().Int32Value());
   }
   // Get concurrency
   return Napi::Number::New(info.Env(), vips_concurrency_get());
@@ -91,8 +91,8 @@ Napi::Value counters(const Napi::CallbackInfo& info) {
 */
 Napi::Value simd(const Napi::CallbackInfo& info) {
   // Set state
-  if (info[0].IsBoolean()) {
-    vips_vector_set_enabled(info[0].As<Napi::Boolean>().Value());
+  if (info[size_t(0)].IsBoolean()) {
+    vips_vector_set_enabled(info[size_t(0)].As<Napi::Boolean>().Value());
   }
   // Get state
   return Napi::Boolean::New(info.Env(), vips_vector_isenabled());
@@ -185,10 +185,10 @@ Napi::Value _maxColourDistance(const Napi::CallbackInfo& info) {
 
   // Open input files
   VImage image1;
-  sharp::ImageType imageType1 = sharp::DetermineImageType(info[0].As<Napi::String>().Utf8Value().data());
+  sharp::ImageType imageType1 = sharp::DetermineImageType(info[size_t(0)].As<Napi::String>().Utf8Value().data());
   if (imageType1 != sharp::ImageType::UNKNOWN) {
     try {
-      image1 = VImage::new_from_file(info[0].As<Napi::String>().Utf8Value().c_str());
+      image1 = VImage::new_from_file(info[size_t(0)].As<Napi::String>().Utf8Value().c_str());
     } catch (...) {
       throw Napi::Error::New(env, "Input file 1 has corrupt header");
     }
@@ -196,10 +196,10 @@ Napi::Value _maxColourDistance(const Napi::CallbackInfo& info) {
     throw Napi::Error::New(env, "Input file 1 is of an unsupported image format");
   }
   VImage image2;
-  sharp::ImageType imageType2 = sharp::DetermineImageType(info[1].As<Napi::String>().Utf8Value().data());
+  sharp::ImageType imageType2 = sharp::DetermineImageType(info[size_t(1)].As<Napi::String>().Utf8Value().data());
   if (imageType2 != sharp::ImageType::UNKNOWN) {
     try {
-      image2 = VImage::new_from_file(info[1].As<Napi::String>().Utf8Value().c_str());
+      image2 = VImage::new_from_file(info[size_t(1)].As<Napi::String>().Utf8Value().c_str());
     } catch (...) {
       throw Napi::Error::New(env, "Input file 2 has corrupt header");
     }