Shortening a Javascript if-else structure

Question

The code I have is:

 var level = function (d) {
    if (value(d) > median + stdev) {
        return 1;
    } else if (value(d) > median) {
        return 2         


        

Answer 1

You can calculate the difference between the value and the median, which makes the comparisons simpler:

function level(d) {
  var n = value(d) - median;
  if (n > stdev) {
    return 1;
  } else if (n > 0) {
    return 2;
  } else if (n > -stdev) {
    return 3;
  } else {
    return 4;
  }
};

You can also write it using the conditional operator instead of if statements:

function level(d) {
  var n = value(d) - median;
  return n > stdev ? 1 :
    n > 0 ? 2 :
    n > -stdev ? 3 :
    4;
  }
};

Whether this is nicer or not is a matter of taste, but it's shorter.