Rotate array and store all combination in object variable

Question

I have month array which should be rotate left to right for its length time. Store all rotational array in object variable. Can you please suggest more efficient way to do it.

var Month = ["Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec"];


 Output looks like:

 monthRotate = {
                      rotate1: ["Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan"],
                      rotate2: ["Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec", "Jan", "Feb"],
                       .
                       .
                       . 
                       .
                      rotate11: ["Dec", "Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov"]; 
             }

I have tried this below method.

var months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];
var rotate = {};
for (var i=1;i<months.length;i++){
	var mts = months.slice(i).concat(months.slice(0,i));
	rotate["rotate"+i] = mts;
}

console.log(rotate);

Answer 1

You can use shift method in order to remove the first element of the given array and then push it at the end of the array.

var months = ["Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec"];
let final = [...Array(months.length-1)].reduce(function(arr){
   months.push(months.shift());
   arr.push([...months]);
   return arr;
},[]);
console.log(final);

Answer 2

You can create rotations array object in this way:

var Month = ["Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sep", "Oct", "Nov", "Dec"];
var rotations = [];
for(var i = 0; i < 11; i++){
    rotations[i] = [];
   for(var j = i+1, k = 0; k < 12; j++, k++){
      if(j === 12){
         j = 0;
      } 
      rotations[i].push(month[j]);
   }
}

Console output: