Task 78. UniLecs. Find a digital root of the number. It equals to sum of all digits until the length is 1.

digitalRoot.js

const digitalRoot = n => {
  return Math.abs((n - 1) % 9 + 1)
}

console.log(digitalRoot(1)) // should be 1
console.log(digitalRoot(11)) // should be 2
console.log(digitalRoot(19)) // should be 1
console.log(digitalRoot(191)) // should be 2
console.log(digitalRoot(1918)) // should be 1
console.log(digitalRoot(65536)) // should be 7