can someone please explain me how does this line of code work.
[].push.apply(perms, permutation(arr.slice(0), start + 1, last));
This function generates an array of all permutations of an input array;
var permutation = function(arr, start, last){
var length = arr.length;
if(!start){
start = 0;
}
if(!last){
last = length - 1;
}
if( last === start){
return [arr];
}
var temp;
var perms = [];
for(var i = start; i < length; i++){
swapIndex(arr, i, start);
console.log(arr);
[].push.apply(perms, permutation(arr.slice(0), start + 1, last));
swapIndex(arr, i, start);
}
return perms;
};