diff --git a/src/lib/ui/Settings.svelte b/src/lib/ui/Settings.svelte
index 741b7f1..e12fa6a 100644
--- a/src/lib/ui/Settings.svelte
+++ b/src/lib/ui/Settings.svelte
@@ -16,7 +16,7 @@
   }
 
   let selectedTheme: ThemeName; // Bound to the settings input.
-  if (themes.hasOwnProperty($settings.theme)) {
+  if (Object.hasOwn(themes, $settings.theme)) {
     selectedTheme = $settings.theme;
   } else {
     selectedTheme = defaultTheme;
diff --git a/src/lib/ui/XTerm.svelte b/src/lib/ui/XTerm.svelte
index 21f2470..6eed2bf 100644
--- a/src/lib/ui/XTerm.svelte
+++ b/src/lib/ui/XTerm.svelte
@@ -67,7 +67,7 @@
   export let termEl: HTMLDivElement = null as any; // suppress "missing prop" warning
   let term: Terminal | null = null;
 
-  $: theme = themes.hasOwnProperty($settings.theme)
+  $: theme = Object.hasOwn(themes, $settings.theme)
     ? themes[$settings.theme]
     : themes[defaultTheme];