casl react redux

import { AbilityBuilder } from 'casl'

function subjectName(item) { 
if (!item || typeof item === 'string') {
    return item  
    }  
return item.__type
}
export default AbilityBuilder.define({ subjectName }, can => {
    can(['read', 'create'], 'Todo') 
    can(['update', 'delete'], 'Todo', { assignee: 'me' })
});