Removing a set users information on logout - angularjs

Question

Good day, am currently struggling to understand why I can not set a user value as null on logout. I have a method used to set the user information so it's accessed globally and a get method to get the users information later on but right now regardless of which user is logged in the previous user data remains.
This is my current service controller:
.factory('UserInfo', [function() {
var user;
return {
get: function(){
return user;
},
set: function(userInfo){
user = userInfo;
},
remove :function(){
user = null;
return user;
}
};
}
])
.factory('Authentication',['UserInfo',function(UserInfo){
return {
user: UserInfo.get()
};
}]);
The function that I am trying to calling out is the remove function in the UserInfo service. Any help will be appreciated.

Answer 1

A factory is a singleton, the first instance created gets used every single time you ask for it. So if you do the following:
.factory('Authentication',['UserInfo',function(UserInfo){
return {
user: UserInfo.get()
};
}]);
.controller('Blabla', ['Authentication', function(Authentication) {
var user = Authentication.user;
}]
you will set user equal to what UserInfo.get() returns at that point. So everytime you call Authentication.user() it will return the same object, regardless of what the UserInfo actually contains.
You can solve this by passing a function instead of the function result. Like so:
.factory('Authentication',['UserInfo',function(UserInfo){
return {
user: UserInfo.get
};
}]);
.controller('Blabla', ['Authentication', function(Authentication) {
var user = Authentication.user();
}]
notice how the () (parenthesis) are gone on the UserInfo.get and they're added on the Authentication.user().