Array.sort().filter(…) with zero in Javascript

Question

Why 0 is not returned by the following filter ?

[0, 5, 4].sort().filter(function(i){return i}) // returns : [4, 5]

Answer 1

To keep 0, but still filter out falsy values, try this:

[0, 5, undefined, 4, null, 7, NaN, -4].sort().filter(function(item){
  return item || item === 0;
});

Edit: Refactored with ES2015 arrow function

[0, 5, undefined, 4, null, 7, NaN, -4].sort().filter(item => item || item === 0);