在庫追加時のエラーを実装

frontend/src/pages/StockPage.tsx

@@ -123,8 +123,21 @@ const StockPage: React.FC = () => {
       if (newStock.newAddition) {
         newStock.stuffId = null;
       }
-      if (isNaN(newStock.amount)) return;
-      if (newStock.price === null || isNaN(newStock.price)) return;
+
+      if (!newStock.stuffId && !newStock.stuffName) {
+        showErrorMessage(GENERAL_ERRORS.INVALID_STUFF_NAME);
+        return;
+      }
+
+      if (isNaN(newStock.amount)) {
+        showErrorMessage(GENERAL_ERRORS.INVALID_AMOUNT);
+        return;
+      }
+
+      if (newStock.price === null || isNaN(newStock.price)) {
+        showErrorMessage(GENERAL_ERRORS.INVALID_PRICE);
+        return;
+      }
 
       if (newStock.buyAmount !== null && isNaN(newStock.buyAmount)) {
         newStock.buyAmount = null;
@@ -684,7 +697,7 @@ const StockPage: React.FC = () => {
               label="購入店舗"
               fullWidth
               value={newStock.shop}
-              onChange={(e) => setNewStock({...newStock, shop: e.target.value})}
+              onChange={(e) => setNewStock({ ...newStock, shop: e.target.value })}
             />
             {/* 購入日・消費期限を横並びに */}
             <Box sx={{ display: 'flex', gap: 2, mb: 2 }}>
@@ -708,7 +721,7 @@ const StockPage: React.FC = () => {
         return (
           <Box sx={{ padding: "1rem" }}>
             <Typography variant="h5" component="h1" gutterBottom
-            onClick={() => setOpenCategory({...openCategory, [category]: !openCategory[category]})}
+              onClick={() => setOpenCategory({ ...openCategory, [category]: !openCategory[category] })}
             >
               {!openCategory[category] ? <ArrowDownIcon color="primary" /> : <ArrowUpIcon color="primary" />}
               {category}