Improve compress script

Generate zst and br files, then  remove any that are actually larger
than the source file

scripts/compress.sh

@@ -1,13 +1,41 @@
 #!/usr/bin/env zsh
 
-if ! type fd &> /dev/null; then
+if ! (( $+commands[fd] )) &> /dev/null; then
     echo "fd not installed"
     exit 1
 fi
 
-if ! type brotli &> /dev/null; then
+if ! (( $+commands[brotli] )) &> /dev/null; then
     echo "brotli not installed"
     exit 1
 fi
 
-fd -e css -e js --search-path ./public/assets --type f -x brotli --force --best --output={}.br {}
+if ! (( $+commands[zstd] )) &> /dev/null; then
+    echo "zstd not installed"
+    exit 1
+fi
+
+# Make .br files
+fd --extension css --extension js --search-path ./public/assets --type f --exec brotli --force --best --output={}.br {}
+# Make .zst files
+fd --extension css --extension js --search-path ./public/assets --type f --exec zstd --quiet --force --ultra -22 --exclude-compressed {} -o {}.zst
+
+# Remove files that actually got bigger!
+fd --extension br --extension zst --search-path ./public/assets --type f --exec sh -c '
+for file; do
+  src="${file%.br}"
+  src="${src%.zst}"
+  if [ -f "$src" ]; then
+    # Get file sizes using stat with cross-platform compatibility
+    if [ "$(uname)" = "Darwin" ]; then
+      file_size=$(stat -f%z "$file")
+      src_size=$(stat -f%z "$src")
+    else
+      file_size=$(stat -c%s "$file")
+      src_size=$(stat -c%s "$src")
+    fi
+    # Compare sizes and conditionally echo rm command
+    [ "$file_size" -ge "$src_size" ] && rm "$file"
+  fi
+done
+' _ {}