Check conditions without instance of class

[bertho-zero]

How is it possible to check abilities with conditions and without instance of class?

One can either pass a string of characters (example: 'Post'), or a class instance where the name of the subject is extracted from the constructor.

How to test an object that is not an instance?

[stalniy]

Would be better to ask questions in gitter chat. Recently such case was discussed.

There are at least 4 ways to handle this :)

• create a temporary model instance with prefilled attrs
• add rules on Object subject
• rethink what you actually want to check (usually it comes up that you want to check the request parameters and the model)
• define a custom subjectName function which can map your object to required model

const ability = new Ability(abilityArray, {
    subjectName(subject) {
      if (subject && subject.subjectType) {
        return subject.subjectType;
      }
    }
  });

  const authSettings = {
    subjectType: 'Post',
    tenant_id,
  };

  const abilityCan = ability.can('read', authSettings);

If doesn't fit your needs, please describe your usecase in details

[bertho-zero]

Thank you, I'm using a variant that defines a non-enumerable property:

const SUBJECT_NAME = Symbol('casl/subjectName');

const abilitySubject = (subjectName, object) => {
  Object.defineProperty(object, SUBJECT_NAME, {
    value: subjectName,
    configurable: true,
    writable: true
  });

  return object;
};

const ability = new Ability(abilityArray, {
  subjectName(subject) {
    if (subject && subject[ SUBJECT_NAME ]) {
      return subject[ SUBJECT_NAME ];
    }
  }
});

const authSettings = {
  tenant_id,
};

const abilityCan = ability.can('read', abilitySubject('Post', authSettings));

[stalniy]

Nice!

[omidh28]

Any changes to this problem lately? Because those solutions seems very hacky 👎