如何在 javascript 函数中使用“fetch”从 API 中填充值

Question

我正在尝试编写一个函数来构建一个数组，其中数组的每个值都是使用唯一 url 从 API 中提取的值，一旦从 API 中获取该值，它就会被推送到现有数组中。

基本上，当调用该函数时，我想为列表中列出的每个股票代码填充一个获取的 API 数据的数组，但到目前为止我似乎没有工作

List: [
                { tick: "AAPL", datePurch: "01/01/2021"},
                { tick: "GOOG", datePurch: "01/01/2021"},
                { tick: "TSLA", datePurch: "01/01/2021"},
                { tick: "J", datePurch: "01/01/2021"},
                { tick: "AMZN", datePurch: "01/01/2021"},
                { tick: "FB", datePurch: "01/01/2021"},
                { tick: "BABA", datePurch: "01/01/2021"},
                { tick: "JNJ", datePurch: "01/01/2021"},
                { tick: "JPM", datePurch: "01/01/2021"},
                { tick: "XOM", datePurch: "01/01/2021"},
                ],

 totalPortfolio(){
        const arr = List.map((i) => (
            fetch(`${IEX.base_url}/stock/${i.tick}/intraday-prices?chartLast=1&token=${IEX.api_token}`)
                .then(response => response.json())
                .then(arr => arr.push(arr))
            ));
        console.log(arr);
    }
  

Answer 1

您需要等待所有提取完成后再记录。

将您的代码修改为 async/await 函数并添加所需的Promise.all()：

const List = [
  { tick: "AAPL", datePurch: "01/01/2021" },
  { tick: "GOOG", datePurch: "01/01/2021" },
  { tick: "TSLA", datePurch: "01/01/2021" },
  { tick: "J", datePurch: "01/01/2021" },
  { tick: "AMZN", datePurch: "01/01/2021" },
  { tick: "FB", datePurch: "01/01/2021" },
  { tick: "BABA", datePurch: "01/01/2021" },
  { tick: "JNJ", datePurch: "01/01/2021" },
  { tick: "JPM", datePurch: "01/01/2021" },
  { tick: "XOM", datePurch: "01/01/2021" },
];

async function getIntradayPrice(tick) {
  const resp = await fetch(`${IEX.base_url}/stock/${tick}/intraday-prices?chartLast=1&token=${IEX.api_token}`);
  return resp.json();
}

async function totalPortfolio() {
  const respPromises = List.map(({ tick }) => getIntradayPrice(tick));
  const respArrays = await Promise.all(respPromises);
  console.log(respArrays);
}