Question

我正在尝试通过汇率来计算以美元为单位的近似价格。我想在 console.log(currency) 中得到结果，但我只是在结束时未定义请帮忙）

(async function() {
    let date = new Date();
    let currency = await searchCurrency();
    await console.log(currency) // result expected
})();


function searchCurrency(){
    if(!localStorage.currency||!JSON.parse(localStorage.currency).date==date.getDate()+'.'+date.getMonth()) 
    { 
        return getCurrency(date);
    } else {
        console.log('LS the same!')   
        return JSON.parse(localStorage.currency).val;
    } 
}

function getCurrency(date){
    var answer;
    var xhr = new XMLHttpRequest();
    var apiKey = "my_key";
    var query = 'RUB' + "_" + 'USD';
    var url =
        "https://free.currconv.com/api/v7/convert?q=" +
        query +
        "&compact=ultra&apiKey=" +
        apiKey;
    
    xhr.open("GET", url);
    xhr.onload = function () {
        if (xhr.status != 200) {
          console.log(`Error ${xhr.status}: ${xhr.statusText}`);
          answer = 80;
        } else {
          console.log(`${xhr.response}`); 
          localStorage.setItem('currency', JSON.stringify({val: JSON.parse(xhr.response)[query], date: date.getDate()+'.'+date.getMonth()}));
        answer = JSON.parse(xhr.response)[query];
        }
      };
  xhr.send();
  return answer;
}

UPD：感谢您的评论和类似问题。我将我的请求函数封装在一个如下面的 promise 中，它现在可以工作了 :) 如果将来对某人有用，请在此处发布。

(async function() {
    let date = new Date();
    let currency;
     if (localStorage.currency&&JSON.parse(localStorage.currency).date==date.getDate()+'.'+date.getMonth()){
        currency = JSON.parse(localStorage.getItem('currency')).val;
     } else {
        currency = await makeRequest(date);
        localStorage.setItem('currency', JSON.stringify({val: currency, date: date.getDate()+'.'+date.getMonth()}))
     }
    await console.log(currency);
})();
function makeRequest(date) {
    return new Promise(function (resolve, reject) {
        let xhr = new XMLHttpRequest();
        xhr.open('GET', 'https://free.currconv.com/api/v7/convert?q=RUB_USD&compact=ultra&apiKey='secret_api_key');
        xhr.onload = function () {
           if (this.status >= 200 && this.status < 300) {
               resolve(JSON.parse(xhr.response).RUB_USD);
           } else {
              reject({
                 status: this.status,
                 statusText: xhr.statusText
              });
           }
        };
        xhr.onerror = function () {
           reject({
              status: this.status,
              statusText: xhr.statusText
           });
        };
        xhr.send();
    });
}

Console.log() 在异步函数中不等待

0 个答案: