Snail -- reverse array

gistfile1.js

// Return an array sorted in a "snail" format -- that is, around the edge and then the middle. 

// var arr =  [[1,2,3],
//         [4,5,6],
//         [7,8,9]];
         
// var arr1 = [[1]];
// var arr2 = [[1, 2], [3, 4]];
         
// Test.assertSimilar(snail(arr1), [1]); 
// Test.assertSimilar(snail(arr), [1,2,3,6,9,8,7,4,5]); 


var snail = function(array) {
  res = [];
  return res.concat(top(array), right(array), bottom(array), left(array), inside(array));
}

function top(array){
  if (array.length < 2) {
    return array[0];
  } 
  return array[0];
}
function right(array){
   if (array.length < 2) {
    return [];
  }
  var res = [];
  for (var i = 1; i<array.length - 1; i++){
    res.push(array[i][array.length - 1]);
  }
  return res;
}
function bottom(array){
  if (array.length < 2) {
    return [];
  }
  return array[array.length - 1].reverse();
}
function left(array){
  if (array.length < 2) {
    return [];
  }
  var res = [];
  for (var i = array.length - 2; i > 0; i--){
    res.push(array[i][0]);
  }
  return res;
}
function inside(array){
  if (array.length < 3) {
    return [];
  }
  
  var res = [];
  
  for (var i = 1; i<array.length - 1; i++){
    res.push(array[i].slice(1, array[i].length - 1));
  }
  
  return snail(res);
  
}