From ab015ef90f95ca8a0acbae971e2edadb4c7162d6 Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Tue, 16 Jun 2020 18:59:20 +0100
Subject: [PATCH] Avoid copy in metadata levels for loop

---
 src/metadata.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/metadata.cc b/src/metadata.cc
index 34d0e4bc..71aa6ec9 100644
--- a/src/metadata.cc
+++ b/src/metadata.cc
@@ -189,7 +189,7 @@ class MetadataWorker : public Napi::AsyncWorker {
       if (!baton->levels.empty()) {
         int i = 0;
         Napi::Array levels = Napi::Array::New(env, static_cast<size_t>(baton->levels.size()));
-        for (std::pair<int, int> const l : baton->levels) {
+        for (std::pair<int, int> const &l : baton->levels) {
           Napi::Object level = Napi::Object::New(env);
           level.Set("width", l.first);
           level.Set("height", l.second);