在没有异步功能的情况下等待响应？

Question

Is it possible to, in a function, wait for the response from an asynchronous function, without making the entire function asynchronous, ala await without async, or something similar? An example of this:

const axios = require('axios');
const converter = require('number-to-words');
const formatter = new Intl.NumberFormat('en-US', {
  style: 'currency',
  currency: 'USD',
});
function dataFetch() {
    //fetches current exchange rate of NOK to USD
    let data = await axios.get('https://api.exchangeratesapi.io/latest?base=NOK');
    //fetches current value of Norwegian Oil fund
    let res = await axios.get('https://www.nbim.no/LiveNavHandler/Current.ashx');
    //extracts value of Norwegian Oil Fund from response data, and converts it to USD in real time.
    let dolla = (res.data.Value.replace(/\s/g, '') * data.data.rates.USD).toFixed(2);
    //Converts Basic number to number with commas, and a dollar sign.
    let val = formatter.format(dolla);
    //Generates word format of number(i.e. one hundred instead of 100)
    let str = converter.toWords(dolla);
    //Generates word format of cents.
    let cents = converter.toWords(dolla.split('.')[1].substring(0, 2));
    //Returns JSON of commaed value and full word string
    return {num: val, word: `${str} dollars and ${cents} cents`};
}
console.log(dataFetch().val);

I want to make sure that the value returned by dataFetch() is the processed version of the data received from the get request, rather than a promise, or null so that the console.log() prints out the value of the fund in dollars, rather than undefined, or null, or something else.

There is almost certainly an easy solution to this, but I cannot seem to find it, and it has been breaking the code I have been working on for a while.

Update : Updated to add context for the problem. I apologize for my slightly unclear comments.

Answer 1

You are making multiple asynchronous (axios) calls inside your dataFetch() function. That means that your function will return BEFORE any of those asynchronous operations are complete and there is nothing you can do about that. That's how asynchronous operations work in Javascript. As such, you cannot return the final value from your function. Your function returns before that final value is known.

There are three options for communicating back the final value:

1. Promise
2. Callback
3. Event

Pick one of those.

In this case, the natural fit would be a promise. You have to declare your dataFetch() function as async anyway so your calls to await in it will be allowed. That means that it will already return a promise automatically. Then to get the value from dataFetch() , you use either await or .then() on the returned promise:

dataFetch().then(result => {
    console.log(result);
}).catch(err => {
    console.log(err);
});

This is how asynchronous programming works in Javascript.

Answer 2

Utilizing the answer I had received, this is the code I went with:

function bimFetch() {
    axios.get('https://api.exchangeratesapi.io/latest?base=NOK').then(data => {
        axios.get('https://www.nbim.no/LiveNavHandler/Current.ashx').then(res => {
            let dolla = (res.data.Value.replace(/\s/g, '') * data.data.rates.USD).toFixed(2);
            let val = formatter.format(dolla);
            let str = converter.toWords(dolla);
            let cents = converter.toWords(dolla.split('.')[1].substring(0, 2));
            if(dolla.split('.') === '01')
                currentStatus = { num: val, word: `${str} dollars and ${cents} cent` };
            else
                currentStatus = { num: val, word: `${str} dollars and ${cents} cents` };
        });
    });
}

Once both of the fetches and the formatting is complete, then it outputs its response to currentStatus . I set a setTimeout() , which after waiting about 5 seconds will send a message with the updated status over all the connected WebSockets.

I would like to thank @jfriend00 for their help on this problem, as I have learned a valuable lesson in JS asynchronous coding.