change AbilityBuilder on state update

I have below code in ability.js

// Defines how to detect object's type
function subjectName(item) {
    if (!item || typeof item === 'string') {
        return item;
    }
    return item.__type;
}

let state = null;
store.subscribe(() => {state = store.getState()});

export default AbilityBuilder.define({subjectName}, can => {
    can('delete', 'Post', {userId: state.auth.userId});
});

and i use redux and react-redux for handling my state in react app

my question is, how can i update my AbilityBuilder when my app’s state updated? because my userId come from state.

thanks 😃

[tanh123678]

i do exactly the same to you but i cant update ability . please tell me why ??? when i logout and login to another user, the ability didn’t update.

[stalniy]

Hi,

You don’t need to update AbilityBuilder. It’s just a helper class. What you want to do is to update rules in your Ability instance.

So, the approximate code should be something like this:

// Defines how to detect object's type
function subjectName(item) {
    if (!item || typeof item === 'string') {
        return item;
    }
    return item.__type;
}

const ability = new Ability([], { subjectName })

let currentAuth;
store.subscribe(() => {
   const prevAuth = currentAuth
   currentAuth = store.getState().auth

   if (prevAuth !== currentAuth) {
      ability.update(defineRulesFor(currentAuth))
   }
});

function defineRulesFor(auth) {
  const { can, rules } = AbilityBuilder.extract()

  can('delete', 'Post', { userId: auth.userId });

  return rules
}

export default ability