Why does this code produce an array of 20 elements which are all undefined:
> Array(20).map(function() { return 3; })
[ , , , , , , , , , , , , , , , , , , , ]
Whereas this code produces an array of 20 elements which are all 3s:
> Array(20).join(' ').split(' ').map(function() { return 3; })
[ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 ]
Why does the first approach not behave as expected?
