var data = [0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1];
function fourier(in_array) {
  var len = in_array.length;
  var output = new Array();
  for (var k = 0; k < len; k++) {
    var real = 0;
    var imag = 0;
    for (var n = 0; n < len; n++) {
      real += in_array[n] * Math.cos( - 2 * Math.PI * k * n / len);
      imag += in_array[n] * Math.sin( - 2 * Math.PI * k * n / len);
    }
    output.push([real,imag])
  }
  return output;
}
fourier(data).forEach(function (element, n)
{
  var x_axis = n;
  var y_axis = Math.round(element[0]);
  console.log('[' + x_axis + '] ' + y_axis);
});