如何从另一个范围返回值

Question

我在 javascript 中的函数内部有一个函数。我在最里面的函数中得到了我的值，但我需要在最外面的函数中返回它。像这样：

import convertPrice from "./convertPrice";
import getCountryInfoByLanguage from "./getCountryInfoByLanguage";
import axios from "axios";
export default (language, price) => {
  let countryCode, currency, formattedPrice;

  navigator.geolocation.getCurrentPosition(position => {
    axios
      .get(
        `http://api.geonames.org/countryCodeJSON?lat=${
          position.coords.latitude
        }&lng=${position.coords.longitude}&username=...`
      )
      .then(response => {
        countryCode = getCountryInfoByLanguage(
          response.data.languages.split(",")[0]
        ).countryCode;
        currency = getCountryInfoByLanguage(
          response.data.languages.split(",")[0]
        ).currency;
        const convertedPrice =
          Math.round(convertPrice(price, currency) * 10) / 10;
        formattedPrice = convertedPrice.toLocaleString(countryCode, {
          style: "currency",
          currency: currency
        });
        console.log(formattedPrice);
        return formattedPrice; //This is where the value gets properly returned
      });

  });
    //this is where I want the value to be returned
};

Answer 1

由于您正在处理 Promise，因此您始终可以返回它们并在最后调用最终的 then。

import convertPrice from "./convertPrice";
import getCountryInfoByLanguage from "./getCountryInfoByLanguage";
import axios from "axios";
export default (language, price) => {
  let countryCode, currency, formattedPrice;

  navigator.geolocation.getCurrentPosition(position => {
    return axios
      .get(
        `http://api.geonames.org/countryCodeJSON?lat=${
          position.coords.latitude
        }&lng=${position.coords.longitude}&username=filipk268`
      )
      .then(response => {
        countryCode = getCountryInfoByLanguage(
          response.data.languages.split(",")[0]
        ).countryCode;
        currency = getCountryInfoByLanguage(
          response.data.languages.split(",")[0]
        ).currency;
        const convertedPrice =
          Math.round(convertPrice(price, currency) * 10) / 10;
        formattedPrice = convertedPrice.toLocaleString(countryCode, {
          style: "currency",
          currency: currency
        });
        console.log(formattedPrice);
        return formattedPrice; //This is where the value gets properly returned
      });

  }).then((data) => {
      console.log(data);
  })
};

请注意，我正在返回 axios 调用，它返回一个承诺，您甚至可以返回 navigator.geolocation.getCurrentPosition，它可以作为当前范围之外的承诺访问。