chaining-promises

old-activation.js

/**
 * Activates a user an obtains a token.
 * @param {string} email Email to activate the user
 * @return {Promise} To be resolved with a token or rejected with an error code.
 */
function activate(email) {
  var defer = $q.defer();

  if (!email) {
    // 1. Check params
    defer.reject(ERROR_CODE.NOT_VALID_PARAMS);
  } else {
    // 2. Get User
    api.getUser(email).then(
      function(user) {
        if (!user) {
          defer.reject(ERROR_CODE.USER_NOT_EXISTS);
        } else {
          // 3. Enables the user
          api.enableUser(user).then(
            function(user) {
                // 4. Obtains a token for the user.
                api.getUserToken(user).then(
                  function(token) {
                    if (token) {
                      // Return obtained token.
                      defer.resolve(token);
                    } else {
                      defer.reject(ERROR_CODE.INVALID_TOKEN);
                    }
                  }, function() {
                    defer.reject(ERROR_CODE.API_ERROR);
                  }
                );
            }, function() {
              defer.reject(ERROR_CODE.API_ERROR);
            }
          );
        }
      }, function() {
        defer.reject(ERROR_CODE.API_ERROR)
      }
    );
  }

  return defer.promise;
}

/**
 * Manages an error showing a log.
 * @param {number} error Error to manage.
 */
function manageError(error) {
  switch(error) {
    case ERROR_CODE.NOT_VALID_PARAMS:
      console.error('Params are not valid');
      break;
    case ERROR_CODE.USER_NOT_EXISTS:
      console.error('User not exists');
      break;
    case ERROR_CODE.INVALID_TOKEN:
      console.error('Token is invalid');
      break;
    case ERROR_CODE.API_ERROR:
      console.error('API has failed');
      break;
  }
}

/**
 * Main function
 */
function main() {
  activate(email)
    .then(function(token) {
      $scope.token = token;
    })
    .catch(manageError);
}