Returning data from promise.all()

Question

I am trying to return data of 3 async api calls using promise.all()

function apiReq1(apiCred){
  const rds = new apiCred.RDS();
  var request = rds.describeDBInstances();
  return request.promise();
}

function getAPIs (apiCred) {
  return Promise.all([apiReq1(apiCred), apiReq2(apiCred), apiReq3(apiCred)]).then(function(data) {
    console.log(data[0])
    console.log(data[1])
    console.log(data[2])
    return data

    // ideal return
    //myMap.set('bar', data[0])
    //.set('foo', data[1])
    //.set('baz', data[2]);
    //return myMap
  });
}

// Function that is calling getAPIs
function getAll() {
  apiCred = getApiCred()
  page = getAPIs(apiCred)
  console.log(page)
}

The console.log prints out the data as expected however I would like to be able to return the data object or ideally a new object with all three iterables to whatever calls getAPIs() . This is the first time I am trying to use promises and I feel there is a key async concept I am missing here on trying to return the data.

Answer 1

You can just do:

function getAPIs (apiCred) {
  return Promise.all([apiReq1(apiCred), apiReq2(apiCred), apiReq3(apiCred)]).then(function(data) {
    return {
        'bar': data[0],
        'foo': data[1],
        'baz': data[2]
    }
  });
}

However, this function still returns a promise, so you cant access the result in the caller synchronously.

You need to modify your getAll method as follows

function getAll() {
  apiCred = getApiCred()
  return getAPIs(apiCred).then(page => {
    console.log(page);
    //DO YOUR THING
  })
}