nbDig.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.

    Implement 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.

    The function, when given n = 25 and d = 1 as argument, should return 11 since
    the k*k that contain the digit 1 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 squared = []

    for(let i = 0; i <= n; i++){
        squared.push(i*i)
    }

    const numString = squared.join('')

    const splitNumString = numString.split('')
    
    return splitNumString.filter(num => num === `${d}`).length
}