How to assign a variable inside a Javascript request-promise

Question

I have an array that I am iterating through. For each element, I would like to call another API and assign the result to an attribute of the element that is currently being looked at.

...

sortedRoutes.forEach(function(route) {

     let myVariable = false;

     var locationdata = {
         uri: `url...`,
         headers: {
           'X-API-KEY': someKey...,
           'User-Agent': 'Request-Promise'
         },
         json: true
      };


     rp(locationdata)
         .then(function(repos) {
             ...
             route.locationInfo = repos.data;
             myVariable = true;
         })
         .catch(function(err) {
            ...
         })


     console.log(myVariable); // false
}

The locationInfo attribute does not get added to each element in the array.

Actually, it turns out any variable that I try to assign in the .then function does not carry its value outside (I have used the myVariable to illustrate what I mean).