code: function count(arr) {
      var c = 0;
      for (var i = 0; i < arr.length; i++) {
          c += eightBits[arr[i] & 0xff] + eightBits[(arr[i] >> 8) & 0xff] + eightBits[(arr[i] >> 16) & 0xff] + eightBits[(arr[i] >> 24) & 0xff];
      }
      return c;
  }
docs: Count the number of true values in an array
  @param {Array} arr
  @return {number}