fix up ts errors

src/classes/NumberMagic.ts

@@ -11,7 +11,8 @@ const damageFormatter = new Intl.NumberFormat('en-US', {
     notation: "compact",
 });
 
-export function formatGold(number: number): string {
+export function formatGold(number: number | null): string {
+    if (number === null) return "";
     return goldFormatter.format(number);
 }
 

src/components/UpgradesList.vue

@@ -18,6 +18,7 @@
       <small>Automatically finish quests when they are completed.</small>
       <button
           class="button metal"
+          v-if="guild.autoFinishQuestsUpgrade.nextLevelCost"
           :disabled="guild.gold < guild.autoFinishQuestsUpgrade.nextLevelCost || guild.autoFinishQuestsUpgrade.isMaxLevel()"
           @click="upgradeAutoFinishQuests()"
       >