np-subsonic: return 1 if nothing is playing

.config/zsh/functions/np-subsonic

@@ -23,4 +23,8 @@ local entry=$(jq '."subsonic-response".nowPlaying.entry[0]' <<<${response})
 local title=$(jq --raw-output .title <<< ${entry})
 local artist=$(jq --raw-output .artist <<< ${entry})
 
-print ${title} – ${artist}
+if [[ "${title}" != "null" && "${artist}" != "null" ]]; then
+    print ${title} – ${artist}
+else
+    return 1
+fi