Sort an array so that null values always come last

Question

I need to sort an array of strings, but I need it so that null is always last. For example, the array:

var arr = [a, b, null, d, null]

When

Answer 1

Use a custom compare function that discriminates against null values:

arr.sort(function(a, b) {
    return (a===null)-(b===null) || +(a>b)||-(a

For descending order, just swap a and b in the direct comparison:

arr.sort(function(a, b) {
    return (a===null)-(b===null) || -(a>b)||+(a