# Pastebin K58kmcVs
function sqrtApproximation(number) {
  number = sqrt(number);
  if(number%1 == 0){
    return number;
  }else{
    return [parseInt(number), parseInt(number)+1];
  }
}

var sqrt = x => {
  var beg=0, last=x,mid;
  do{
    mid = (beg+last)/2;
    if(mid*mid>x){
      last=mid;
    }
    else{
      beg=mid;
    }
  }while(!(abs(mid*mid - x)<0.00000000000001));
    return mid;
}

var abs = x => {
  if(x>0){
    return x;
  }else{
    return -x;
  }
}
>undefined
>sqrtApproximation(9)
>[3, 4]