src/Utl.js
function reverse(a) {
  var len = a.length;
  for (var i = 0; i < Math.floor(len/2); i++) {
    [a[i], a[len-i-1]] = [a[len-i-1], a[i]];
  }
  return a;
}
function reverse(a) {
  var len = a.length;
  for (var i = 0; i < Math.floor(len/2); i++) {
    [a[i], a[len-i-1]] = [a[len-i-1], a[i]];
  }
  return a;
}
function reverse ( a ) { var len = a . length ; for ( var i = 0 ; i < Math . floor ( len / 2 ) ; i ++ ) { [ a [ i ] , a [ len - i - 1 ] ] = [ a [ len - i - 1 ] , a [ i ] ] ; } return a ; }
reverse an array in place
reverse an array in place