permutation string

permutation.js

function nextPerm (str) {
  var arr = str.split("").reverse();
  for (var i=1; i<arr.length; ++i) {
    if ( arr[i] < arr[i-1] ) {
      break;
    }
  };
  if ( i >= arr.length ) {
    return false;
  };
  var remove = arr[i];
  var lowArr = arr.splice(0,i+1);
  lowArr.sort(function(a,b) {return a<b;});
  var insert = lowArr.splice( lowArr.indexOf(remove) -1 , 1 );
  return lowArr.concat(insert, arr).reverse().join("");
}

var start = "abcde";
for (var i=0; i<120; ++i) {
  console.log(start);
  start = nextPerm(start);
};