只有在所有檢查都通過后才更新

我只想在所有檢查都通過后更新物件陣列。我有代表所有文章的物件陣列和所有可用庫存的其他物件陣列。

我想檢查是否所有文章都有庫存，那么我只想更新庫存陣列。這是我的代碼：

const articles = [{
    "id": "1",
    "quantity": "4"
}, {
    "id": "2",
    "quantity": "8"
}, {
    "id": "4",
    "quantity": "1"
}];

let stock = [
    {
      "id": "1",
      "stock": "6"
    },
    {
      "id": "2",
      "stock": "6"
    },
    {
      "id": "3",
      "stock": "2"
    },
    {
      "id": "4",
      "stock": "2"
    }
  ];

articles.map(article => {
  stock.map(inventItem => {
    if(inventItem.id === article.id){
      if(article.quantity <= inventItem.stock){
        inventItem.stock = inventItem.stock - article.quantity;
      } else {
             console.log('error');
             throw error;
      }
    }
   });
 });

這個解決方案的問題是它會更新庫存，id = 1即使id = 2還不夠。我正在嘗試檢查所有商品是否有足夠的數量并在庫存陣列中更新（減去）它們。所以在這種情況下，代碼將像這樣更新股票陣列：

stock = [
    {
      "id": "1",
      "stock": "2"
    },
    {
      "id": "2",
      "stock": "6"
    },
    {
      "id": "3",
      "stock": "2"
    },
    {
      "id": "4",
      "stock": "2"
    }
  ];

有人可以建議我如何解決這個問題嗎？

uj5u.com熱心網友回復：

您可以使用Array.prototype.find(). 注意：該片段假定所有文章都有一個"id"屬性，它不檢查"art_id".

const articles = [{
  "id": "1",
  "quantity": "4"
}, {
  "id": "2",
  "quantity": "8"
}, {
  "id": "4",
  "quantity": "1"
}];

let stock = [{
    "id": "1",
    "stock": "6"
  },
  {
    "id": "2",
    "stock": "6"
  },
  {
    "id": "3",
    "stock": "2"
  },
  {
    "id": "4",
    "stock": "2"
  }
];


// Use Array.prototype.some() to check for items that don't have enough stock
const haveEnough = !articles.some(article =>
  // Turns "1" into 1
  parseInt(
    // Find the stock with the same id as the article
    stock.find(stock => stock.id === article.id).stock
  ) <
  parseInt(article.quantity))

console.log(haveEnough)

然后你可以stock更新

if (haveEnough) {
 // Do something
}

uj5u.com熱心網友回復：

我假設陣列中的art_id鍵articles應該是id.

不幸的是，您不能在一個回圈中完成所有操作，而是必須先遍歷所有文章以了解它們的庫存是否足夠，然后再次遍歷它們以更改現有庫存：

const articles = [
  {
    id: '1',
    quantity: '4',
  },
  {
    id: '2',
    quantity: '5',
  },
  {
    id: '4',
    quantity: '1',
  },
];

let stock = [
  {
    id: '1',
    stock: '6',
  },
  {
    id: '2',
    stock: '6',
  },
  {
    id: '3',
    stock: '2',
  },
  {
    id: '4',
    stock: '2',
  },
];

// Are there any articles that do not have enough stock
const outOfStockArticles = articles.find((article) => {
  const articleStock = stock.find((stock) => stock.id === article.id);
  return Number.parseInt(article.quantity) > Number.parseInt(articleStock.stock);
});

// If there are no out of stock articles - change existing stock values
if (!outOfStockArticles) {
  articles.forEach((article) => {
    const articleStock = stock.find((stock) => stock.id === article.id);
    articleStock.stock = Number.parseInt(articleStock.stock) - Number.parseInt(article.quantity);
  });
}

uj5u.com熱心網友回復：

您的文章陣列中存在不一致，我想每篇文章都有一個“art_id”，而不是一些“id”和一些“art_id”。

您可以使用 Array.prototype.find 函式簡單地找到您的文章，然后通過isAvailable函式檢查庫存串列中的文章數量是否正確。

現在你可以使用 Array.prototype.every 函式來做你想要的！只有當陣列的每個元素都滿足條件時，它才會回傳 true，在我們的例子中是isAvailable函式。

這是一個簡單的小提琴：

const articles = [{
  "art_id": "1",
  "quantity": "4"
}, {
  "art_id": "2",
  "quantity": "8"
}, {
  "art_id": "4",
  "quantity": "1"
}];

const stock = [{
    "id": "1",
    "stock": "6"
  },
  {
    "id": "2",
    "stock": "6"
  },
  {
    "id": "3",
    "stock": "2"
  },
  {
    "id": "4",
    "stock": "2"
  }
];


const isAvaiable = (article) => {
  return stock.find(element => element.id === article.art_id).stock >= article.quantity;
}

if (articles.every(isAvaiable)) {
  console.log("I can update")
} else {
  console.log("I cannot update")
}

標籤：javascript 数组 打字稿

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