function lastdigit() {
var n = prompt('Enter number ', 27);
n = n % 10;
alert("last digit = " +n);
}
lastdigit();
const digitsText = ['zero', 'one', 'two', ..., 'nine'];
const getLastDigitAsText = (number) => digitsText[number % 10];
getLastDigitAsText(1234); // four