承诺{< pending> }-试图等待.map [英] Promise { <pending> } - Trying to await for .map

问题描述

我正在使用.map绘制新对象并将旧价格添加到地图中.

I am using .map to map out a new object and to add the old price to the map.

我正在对数据映射使用Async/Await，这是我的代码:

I am using Async/Await with my datamaps, here is what my code looks like:

let datasets = await changes.map(async (data) => {
  let products = {};
  let last = await models.prices.findOne({
    where: {
        productId: data.productId,
        sourceId: data.sourceId
    },
    order: [['createdAt', 'DESC']],
    limit: 1,
    offset: 1
  });

  products.name   = data.product.name;
  products.price  = data.price;
  products.sku    = data.product.sku;
  products.source = data.source.name;
  products.link   = data.link;
  products.diff   = last.price;


  return products;
});

changes是最近24小时内发现的所有价格变动.

changes are all of the prices changes found in the last 24 hours.

last包含上次发现特定产品的价格变化的时间.

last contains the previous time a price change was found of the particular product.

return products不在等待中，因此我收到了Promise { <pending> }邮件的垃圾邮件.如果使用console.log(last)，它将在内部运行，但是我无法找出减慢返回速度的正确方法.

The return products isn't waiting, so I get a spam of Promise { <pending> } messages. If I use a console.log(last) it's working inside, but I cannot figure out the correct way to slow down the return.

products.diff = last.price是需要填充才能使此有效的一件.有什么想法吗?

products.diff = last.price is the one piece that needs to fill for this to be valid. Any ideas?

推荐答案

await等待Promises，但Array.prototype.map返回一个新的Promises数组.您需要用Promise.all

await awaits on Promises but Array.prototype.map returns a new array of Promises. You need to wrap it with Promise.all

let datasets = await Promise.all(changes.map(async (data) => {
  let products = {};
  let last = await models.prices.findOne({
    where: {
        productId: data.productId,
        sourceId: data.sourceId
    },
    order: [['createdAt', 'DESC']],
    limit: 1,
    offset: 1
  });

  products.name   = data.product.name;
  products.price  = data.price;
  products.sku    = data.product.sku;
  products.source = data.source.name;
  products.link   = data.link;
  products.diff   = last.price;


  return products;
}));

这篇关于承诺{< pending> }-试图等待.map的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！