arraySliceEveryN(array, n)

arraySliceEveryN.js

/**
 * Slice an array every n elements. Don't leave out any elements from source array or
 *  empty spaces in the resulting slices.
 * @example
 * arraySliceEveryN([1,2,3,4,5,6,7], 3)
 * //=> [[1,4,7],[2,5],[3,6]]
 */
function arraySliceEveryN(array, n) {
    let slices = Array(n);
    const min_len = Math.floor(array.length / n); // Length without remaining elements
    const rem = array.length - n * min_len; // Remaining elements
    for (let m = 0; m < n; m++) { // Initialize slices
        slices[m] = Array(min_len + (rem - m > 0 ? 1 : 0));
    }
    for (let i = 0; i < array.length; i++) {
        slices[i % n][Math.floor(i / n)] = array[i];
    }
    return slices;
}