Calling two APIs within the same Geolocation function

[Giampi71]

I'm trying to call 2 APIs that require location as input (say for example 2 weathers provider). The 2 fetch functions are therefore included into the same response "locationSuccess(position)". 

My problem is very simple and I'm sure kinda stupid for developers but I'm very beginner: how do I merge the results returned by the 2 fetch before to send them back to the device?

I have something like 

fetch(ENDPOINT_weatherproviderlink1)
  .then(function (response) {
      response.json()
      .then(function(data) {
        // We just want some data
        var weather1 = {
          temperature: data["temp"]
        }
      });
  })
  .catch(function (err) {
    console.log("Error fetching weather: " + err);
  });
 };

fetch(ENDPOINT_weatherproviderlink2)
  .then(function (response) {
      response.json()
      .then(function(data) {
        // We just want some data
        var weather2 = {
          temperature: data["temp"]
        }
      });
  })
  .catch(function (err) {
    console.log("Error fetching weather: " + err);
  });
 };

 // Send the weather data to the device returnWeatherData(weather);
 // merge weather1 + weather2 ??????

[JonFitbit · Accepted solution]

You can use promise.all to perform multiple fetch() commands and wait for the results.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all

Some examples here https://stackoverflow.com/questions/31710768/how-can-i-fetch-an-array-of-urls-with-promise-all#31711...

[Giampi71]

Thanks @JonFitbit. It definitely looks "promising" (see what I did here! )However also very complex, time to put my head in the books!