Find minimum, except zero

Question

I'm using Math.min() to find the lowest price, but the variables passed might have 0 sometimes if the product is unavailable:

Math.min( 101.06, 99.99, 0 );

.. in this case, the result is 0. How do I filter it out?

Answer 1

I'm guessing you want the smallest positive number:

function positiveMin(arr) {
  var min;
  arr.forEach(function(x) {
    if (x <= 0) return;
    if (!min || (x < min)) min = x;
  });
  return min;
}

positiveMin([101.06, 99.99, 0, -1]); // => 99.99
positiveMin([0]); // => undefined

Answer 2

You can use .apply to pass arguments as an array,

fun.apply(thisArg, [argsArray])

^{- https://developer.mozilla.org/}

This means that you can filter your arguments, checking for any properties you would like.

So, in your case just do:

Math.min.apply(this, [101.06, 99.99, 0].filter(Number) );

This method has other benefits as well, it seems like you would be dynamically generating your arguments, and it would be easier to pass a generated array than actual arguments.

Answer 3

Here's a simple function:

Math.positiveMin = function(){
  arguments = Array.prototype.slice.call(arguments);
  return arguments.reduce(function(min, current){
    return (current > 0 && current < min) ? current : min;
  }, arguments[0]);
};

returns zero if there are no arguments greater than 0.

Possible benefit of this method over my previous: you were passing arguments individually in your example, and you can do that with this method:

Math.positiveMin( 101.06, 99.99, 0 );

will work just as you expect, no need for an array.