Update Password : getASecureRandomPassword is not defined

Hello, this code for updating password is not working to my JavaScript app. It always send that "getASecureRandomPassword" is not defined. Here is the code :

const user = auth.currentUser;
const newPassword = getASecureRandomPassword();

updatePassword(user, newPassword)
.then(function() {
// Update successful.
}).catch(function(error) {
// An error happened.
});