How to get Last digit of number

var sampleNumber = 123456789,
  lastDigit = sampleNumber % 10;
console.log('The last digit of ', sampleNumber, ' is ', lastDigit);

var sampleNumber = 12345678.89,
  lastDigit = Number.isInteger(sampleNumber) ? sampleNumber % 10
    : sampleNumber.toString().slice(-1);
console.log('The last digit of ', sampleNumber, ' is ', lastDigit);