diff --git a/Userland/Libraries/LibJS/Runtime/TypedArray.h b/Userland/Libraries/LibJS/Runtime/TypedArray.h
index 0ea87b77d5..603d0ef63e 100644
--- a/Userland/Libraries/LibJS/Runtime/TypedArray.h
+++ b/Userland/Libraries/LibJS/Runtime/TypedArray.h
@@ -63,9 +63,19 @@ public:
     // NOTE: In error cases, the function will return as if it succeeded.
     virtual bool put_by_index(u32 property_index, Value value) override
     {
-        // FIXME: If O.[[ContentType]] is BigInt, let numValue be ? ToBigInt(value).
-        //        Otherwise, let numValue be ? ToNumber(value).
-        //        (set_value currently takes value by itself)
+        auto& vm = this->vm();
+        auto& global_object = this->global_object();
+
+        Value num_value;
+        if (content_type() == TypedArrayBase::ContentType::BigInt) {
+            num_value = value.to_bigint(global_object);
+            if (vm.exception())
+                return {};
+        } else {
+            num_value = value.to_number(global_object);
+            if (vm.exception())
+                return {};
+        }
 
         if (!is_valid_integer_index(property_index))
             return true;
@@ -82,7 +92,7 @@ public:
             return true;
         }
 
-        viewed_array_buffer()->template set_value<T>(indexed_position.value(), value, true, ArrayBuffer::Order::Unordered);
+        viewed_array_buffer()->template set_value<T>(indexed_position.value(), num_value, true, ArrayBuffer::Order::Unordered);
 
         return true;
     }