Quasar qpopup edit async validation not working

Question

I am facing issue with qpopupedit async validation I created a codepen. I think it is converting return boolean value to a string. can anyone check why it is not working ?

I created a Codepen you can check

async function validatecalories (val){
      errorCalories.value = true;
      errorMessageCalories.value = 'async error';
      return new Promise(function (resolve, reject) {
        setTimeout(function (){
          reject(false); 
          }, 300);
      });
    }