diff --git a/AK/String.cpp b/AK/String.cpp
index 9fa21d78768..d49d70bad69 100644
--- a/AK/String.cpp
+++ b/AK/String.cpp
@@ -468,11 +468,12 @@ ErrorOr<String> String::repeated(String const& input, size_t count)
     return result;
 }
 
-String String::bijective_base_from(size_t value, Case target_case, unsigned base, StringView map)
+String String::bijective_base_from(size_t value, Case target_case, unsigned base, Optional<StringView> maybe_map)
 {
     value++;
-    if (map.is_null())
-        map = target_case == Case::Upper ? "ABCDEFGHIJKLMNOPQRSTUVWXYZ"sv : "abcdefghijklmnopqrstuvwxyz"sv;
+    if (!maybe_map.has_value())
+        maybe_map = target_case == Case::Upper ? "ABCDEFGHIJKLMNOPQRSTUVWXYZ"sv : "abcdefghijklmnopqrstuvwxyz"sv;
+    auto map = maybe_map.release_value();
 
     VERIFY(base >= 2 && base <= map.length());
 
diff --git a/AK/String.h b/AK/String.h
index 09e6cf0f0f4..71a34efd7ff 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -92,7 +92,7 @@ public:
         Upper,
         Lower,
     };
-    [[nodiscard]] static String bijective_base_from(size_t value, Case, unsigned base = 26, StringView map = {});
+    [[nodiscard]] static String bijective_base_from(size_t value, Case, unsigned base = 26, Optional<StringView> map = {});
     [[nodiscard]] static String greek_letter_from(size_t value);
     [[nodiscard]] static String roman_number_from(size_t value, Case);