message: No negative numbers
diff: @@ -66,7 +66,7 @@ const StoreProto = {
  // Some things can't have multiple stacks.
  if (item.uniqueStack) {
  - return item.maxStackSize - this.amountOfItem(item);
  + return Math.max(item.maxStackSize - this.amountOfItem(item), 0);
  }
  const occupiedStacks = this.buckets[item.bucket.id] ? this.buckets[item.bucket.id].length : 10;
  