Array.map doesn't seem to work on uninitialized arrays

Question

I\'m trying to set default values on an uninitialized array using the map function but it doesn\'t seem to work, any ideas on how to set default values?

Consider thi

Answer 1

You can populate an array with zeros using this function:

function fillArrayWithNumber(n) {
  var arr = Array.apply(null, Array(n));
  return arr.map(function (x, i) { return 0; });
}

fillArrayWithNumber(5); // [0,0,0,0,0]

Or with a small change you can use indexes instead:

function fillArrayWithIndex(n) {
  var arr = Array.apply(null, Array(n));
  return arr.map(function (x, i) { return i; });
}

fillArrayWithIndex(5); // [0,1,2,3,4]

Fiddle