diff --git a/script/nsfw-warning.ts b/script/nsfw-warning.ts
index 8bcb319..25a783a 100644
--- a/script/nsfw-warning.ts
+++ b/script/nsfw-warning.ts
@@ -1,12 +1,8 @@
 const nsfwOk = 'nsfw-ok';
 
-function alreadyYes() {
-  return localStorage.getItem(nsfwOk) == '1';
-}
-
 function dismiss() {
   const dialog = document.getElementById('nsfw-dialog')!;
-  dialog.parentElement?.removeChild(dialog);
+  dialog.parentElement!.removeChild(dialog);
 }
 
 function yes() {
@@ -15,7 +11,7 @@ function yes() {
 }
 
 function setup() {
-  if (alreadyYes()) {
+  if (localStorage.getItem(nsfwOk)) {
     dismiss();
   } else {
     document.getElementById('nsfw-yes')!.onclick = yes;
diff --git a/script/single.ts b/script/single.ts
index e5f1c08..306d117 100644
--- a/script/single.ts
+++ b/script/single.ts
@@ -47,7 +47,7 @@ function setImage(id: string, src: string, href: string, cw: string): void {
 function activateButton(button: HTMLInputElement, doPush = true): void {
   setImage(button.id, button.value,
            button.dataset.link!,
-           button.dataset.warning!);
+           button.dataset.warning ?? '');
 
   if (doPush) history.pushState(null, '', '#' + button.id);
 }