Check if exist any Key localStorage Javascript

Question

I need to check if there is any key in localStorage This code did not work

    if (localStorage.user === undefined) {
      alert('There is no key!'); 
    }

Answer 1

You need to use getItem

if (localStorage.getItem("user") === null) {
    alert('Não há chave!'); 
}

EDIT You can check if the localstorage is empty by

if (localStorage.length == 0)

Answer 2

if (Object.keys(localStorage).length === 0) {
  alert('There is no key!'); 
}