example of using defer

chaining.js

function getAllUsers() {
  let promise = $http.get('/settings')
    .then((settings) => {
      if(settings.defaultUsers) {
        return getDefaultUsers();
      }
      else {
        // get some more data
        return $http.get('/users')
          .then((users) => {
            // do something else with the users
            return users;
          })
      }
    })
    
  promise
    .then(() => {
      // do something else
    })
    .catch(() => {
      
    })
  return promise;
}

defer.js

function getAllUsers() {
  let deferred = $q.defer();
  $http.get('/settings')
    .then((settings) => {
      if(settings.defaultUsers) {
        deferred.resolve(getDefaultUsers());
      }
      else {
        // get some more data
        return $http.get('/users')
          .then((users) => {
            // do something else with the users
            deferred.resolve(users);
          })
      }
    })
    .then(() => {
      // do something else
    })
    .catch(() => {
      deferred.reject();
    })
  return deferred.promise;
}

Opinionated no defer:

function getAllUsers() {
  let promise = $http.get('/settings').then(settings => {
      if(settings.defaultUsers) {
        return getDefaultUsers();
      }
      // get some more data
      return $http.get('/users').then((users) => {
            // do something else with the users
            return users;
      });    
  });
  // personally, I almost never "fork" promises like in the example above, but you
  // can do it here
  return promise;  
}

Opinionated proxy:

function getAllUsers() {
    let settings = $http.get("/settings");
    let settingUsers = settings.then(settings => settings.defaultUsers ? getDefaultUsers() : null);
    let users = settingUsers.then(users => users || getUsersFromHttp());
    return users;

    function getUsersFromHttp(){ 
        return $http.get(users).then(users => {
            // do processing of users and return processed, I guess
        });
    }
}