unable to update object using hooks in react

I have a function that will update my object value depending on the app name using useState hook. But I am not able to use the hook, it gives error invalid hook call.

Any other way to achieve the same will also work.

var myfun = (function() {

  const APP_NAME= "sample app"
  const [object, setObject] = useState({obj: 'value'})

  if(APP_NAME =="sample app") {
        setObject({obj:'new value'})
         console.log('here')
     }
      return obj
});

myfun();