“periksa apakah fungsi async javascript” Kode Jawaban

periksa apakah fungsi async javascript

let promise = fnThatYouWannaCheck();

if(promise && typeof promise.then === 'function' 
   && promise[Symbol.toStringTag] === 'Promise')
{
  	// is compliant native promise implementation
}
else
{
  	throw new Error('async function expected');
}