Node.js 在array.foreach Sequelize中查询数据库

使用array.forEach修改sequelize中的resultset

我想循环返回的shoppingCart，访问每个元素的数据库，添加一些属性并返回

const promiseInvoices = [];

  await ShoppingCart.findAll({
    where: {
      // eslint-disable-next-line object-shorthand
      cart_id: cartItem.cart_id,
    },
  }).then(result => {
   result.forEach(cartItem2 => {
      const prod = Product.findByPk(cartItem2.product_id);
      console.log(prod);

      let cartItem3 = {};
      const total = prod.price * cartItem2.quantity;
      cartItem3.cart_id =  cartItem2.cart_id;
      cartItem3.product_id =cartItem2.product_id;
      cartItem3.attributes  =cartItem2.attributes;
      cartItem3.quantity  =cartItem2.quantity ;
      cartItem3.price = prod.price;
      cartItem3.name = prod.name;
      cartItem3.image = prod.image2;
      cartItem3.item_id = cartItem2.item_id;
      cartItem3.subtotal = total;

    return promiseInvoices.push(cartItem3);
    });
  });

返回shoppingCart，访问每个shoppingCart对象的数据库，并获取产品以填写每个shoppingCart项目的值。对Product.findByPk的调用将返回如下可用承诺：

Promise [Object] {
      _bitField: 0,
      _fulfillmentHandler0: undefined,
      _rejectionHandler0: undefined,
      _promise0: undefined,
      _receiver0: undefined }

所有Sequelize CRUD调用都是异步的，这意味着它们返回一个承诺，因此您必须等待它们。返回的是

Promise

对象而不是包含详细信息的产品，这是因为您没有等待

findByPk

调用完成

forEach

构造不支持异步操作。即使将

array.forEach

回调设置为异步，它也不会工作，并且仍然返回

Promise

对象，而不是包含详细信息的产品

要解决此问题，您需要等待async

findByPk

调用，并使用支持异步操作的循环。您可以将循环用于您的用例

const promiseInvoices = []

await ShoppingCart.findAll({
    where: {
        cart_id: cartItem.cart_id
    }
}).then(result => {

    // for...of loop that supports await
    for await (const cartItem2 of result){
        // Make sure to wait on all your sequelize CRUD calls
        const prod = await Product.findByPk(cartItem2.product_id)

        // It will now wait for above Promise to be fulfilled and show the proper details
        console.log(prod)

        let cartItem3 = {}
        const total = prod.price * cartItem2.quantity
        cartItem3.cart_id = cartItem2.cart_id
        cartItem3.product_id = cartItem2.product_id
        cartItem3.attributes = cartItem2.attributes
        cartItem3.quantity = cartItem2.quantity
        cartItem3.price = prod.price
        cartItem3.name = prod.name
        cartItem3.image = prod.image2
        cartItem3.item_id = cartItem2.item_id
        cartItem3.subtotal = total

        // Simple push will work in this loop, you don't need to return anything
        promiseInvoices.push(cartItem3)
    }
})

---

完美的我在结果之前添加了async，效果很好。谢谢