Convert to binary from decimal and vice versa

binary-to-decimal.js

function binToDec(n) {
  var result = 0;
  var s = n.toString();
  var len = s.length - 1;
  for (var i = len; i >= 0; i--) {
    result += s[i] * Math.pow(2, len-i);      
  }
  return result;
}

/*
example: 1010010
0 * 2^0
1 * 2^1
0 * 2^2
0 * 2^3
1 * 2^4
0 * 2^5
1 * 2^6
result = 82
*/

decimal-to-binary.js

function decToBin(n) {
  var result = '';
  
  // find highest integer power of 2 equal or less then n
  var order = Math.floor(Math.log2(n));
  
  while (order >= 0) {
    var k = Math.pow(2, order);
    
    // if n >= 2^order - reduce that value from n and add 1 to result
    if (n >= k) {
      n = n - k;
      result += 1;
    } else {
    // else add 0
      result += 0;
    }

    // reduce order by 1
    order = order - 1;
  }

  return result;
}