Is it possible to retrieve a variable from outside a `.then` block within a promise?

Question

Is it possible to retrieve a variable from outside a `.then` block within a promise?

I'm currently developing a Spotify application. I've successfully implemented the login functionality and obtained my token. However, I have encountered an issue where I am unable to access a specific variable outside of a method, in this case being "getCurrentUser".

Below is the method causing me trouble:


function getUser() {
  if ($localStorage.token == undefined) {
    throw alert("Not logged in");
  } else {
    Spotify.getCurrentUser().then(function(data) {
      var names = JSON.stringify(data.data.display_name);
      console.log(names)
    })
  }
};

Although I am able to log the name variable correctly in the console, when I call the getUser() function, it returns undefined. Even with attempting to return the names variable, I still encounter the same issue.

The solution I am seeking involves utilizing $scope for that variable.

javascript angularjs angular-promise

Answer 1

Answer №1

getUser() method is failing to return any value. To fix this, you need to ensure that the promise returned by Spotify.getCurrentUser() is properly handled and the value is returned within the outer function.

function getUser() {

    if ($localStorage.token == undefined) {
        throw alert("Not logged in");
    }
    else {
        return Spotify.getCurrentUser().then(function(data) {
            var names = JSON.stringify(data.data.display_name);
            console.log(names)
            return names;
        })
    }
}

The explanation above addresses the issue of receiving undefined when calling getUser(). However, to utilize the end result effectively, you must adjust how you handle the value from getUser - it returns a promise object, not the final result. Therefore, your code should invoke the promise's then method once the promise is resolved:

getUser()                        // this returns a promise...
   .then(function(names) {       // `names` contains the resolved value from the promise...
      $scope.names = names;      // now you can assign it to your $scope
   });

Answer 2

getUser() method is failing to return any value. To fix this, you need to ensure that the promise returned by Spotify.getCurrentUser() is properly handled and the value is returned within the outer function.

function getUser() {

    if ($localStorage.token == undefined) {
        throw alert("Not logged in");
    }
    else {
        return Spotify.getCurrentUser().then(function(data) {
            var names = JSON.stringify(data.data.display_name);
            console.log(names)
            return names;
        })
    }
}

The explanation above addresses the issue of receiving undefined when calling getUser(). However, to utilize the end result effectively, you must adjust how you handle the value from getUser - it returns a promise object, not the final result. Therefore, your code should invoke the promise's then method once the promise is resolved:

getUser()                        // this returns a promise...
   .then(function(names) {       // `names` contains the resolved value from the promise...
      $scope.names = names;      // now you can assign it to your $scope
   });

Answer 3

Answer №2

By following this approach, you can make use of the await function

function fetchUser() {

    if ($localStorage.token == undefined) {
        throw alert("User not logged in");
    }
    else {
        return Spotify.getUserDetails().then(function(response) {
            var userNames = JSON.stringify(response.data.displayName);
            console.log(userNames)
            return userNames;
        });
    }
}

const userNames = await fetchUser();

Answer 4

By following this approach, you can make use of the await function

function fetchUser() {

    if ($localStorage.token == undefined) {
        throw alert("User not logged in");
    }
    else {
        return Spotify.getUserDetails().then(function(response) {
            var userNames = JSON.stringify(response.data.displayName);
            console.log(userNames)
            return userNames;
        });
    }
}

const userNames = await fetchUser();

Is it possible to retrieve a variable from outside a `.then` block within a promise?

Answer №1

Answer №2

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