Count the Digit.js

// Take an integer n (n >= 0) and a digit d (0 <= d <= 9) as an integer. Square all numbers k (0 <= k <= n) between 0 and n. Count the numbers of digits d used in the writing of all the k**2. Call nb_dig (or nbDig or ...) the function taking n and d as parameters and returning this count.

// #Examples:

// n = 10, d = 1, the k*k are 0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100
// We are using the digit 1 in 1, 16, 81, 100. The total count is then 4.

// nb_dig(25, 1):
// the numbers of interest are
// 1, 4, 9, 10, 11, 12, 13, 14, 19, 21 which squared are 1, 16, 81, 100, 121, 144, 169, 196, 361, 441
// so there are 11 digits `1` for the squares of numbers between 0 and 25.
// Note that 121 has twice the digit 1.

function nbDig(n, d) {
  let sum = 0

  for (let i = 0; i <= n; i++) {
    let num = i ** 2 + ''
    num = num.split('').filter((dig) => dig == d + '')
    sum += num.length
  }
  return sum
}

console.log(nbDig(5750, 0), 4700)
// console.log(nbDig(11011, 2), 9481)
// console.log(nbDig(12224, 8), 7733)
// console.log(nbDig(11549, 1), 11905)