javascript - Binomial sub arrays -

i have array n length. want take possible k (0

for example, if have a's length five:

[1,2,3,4,5] 

and if k = 3, algorithm must give me b array.

[1,2,3    ] [1,2,  4  ] [1,2,    5] [1,  3,4  ] [1,  3,  5] [1,    4,5] [  2,3,4  ] [  2,3,  5] [  2,  4,5] [    3,4,5] 

length of b equal n!/k!(n-k)! ('!' means factorial, newtons method)

i'm using javascript, in tags included it, it's algorithm, not necessary written in javascript.

below copy-paste 1 of projects. don't know if still works ;)

var choose = function choose_func(elems, len) {   var result = [];   (var i=0; i<elems.length; i++) {     if (len == 1) {       result.push([elems[i]]);     } else {       var remainingitems = choose_func(elems.slice(i+1, elems.length), len - 1);       (var j=0; j<remainingitems.length; j++)          result.push([elems[i]].concat(remainingitems[j]));      }   }   return result; };  var result = choose([1,2,3,4,5], 3)  /*result  = [[1,2,3],[1,2,4],[1,2,5],[1,3,4],[1,3,5],              [1,4,5],[2,3,4],[2,3,5],[2,4,5],[3,4,5]] */