Spiral or Snail sort

spiralSort.js

// Sort an array in "Spiral" fashion, something like a snail
const spiral = (arr) => {
        let out = [];
        let k;

        while (arr.length) {
                // top
                while (k = arr[0].shift()) { out.push(k); }
                arr.shift();
                if (!arr.length) {
                        return out;
                }
                //right
                for (let i=0;i<arr.length; i++) {
                        out.push(arr[i].pop());
                }
                //bottom
                while (k = arr[arr.length-1].pop()) { out.push(k)}
                arr.pop();
                //left
                for (let i=arr.length-1;i>=0;i--) {
                        out.push(arr[i].shift());
                }
        }
        return out;
}

const arr = [[1,2,3,4],
                [12,13,14,5],
                [11,16,15,6],
                [10,9,8,7]
];
console.log(spiral(arr));

console.log(spiral([[1,2],[4,3]]));

console.log(spiral([[1,2,3],[8,9,4],[7,6,5]]));