//@ts-check

/**

*@author Damola Adekoya

* @param {Array} arr

*/

const mergeSort = arr => {

if (arr.length <= 1) return arr; //determine the end condition for recursive loop

let mid = Math.floor(arr.length / 2);

let left = mergeSort(arr.slice(0, mid));

let right = mergeSort(arr.slice(mid, arr.length));

return merge(left, right);

};

/**

*

* @param {Array} arr1

* @param {Array} arr2

*/

const merge = (arr1, arr2) => {

let result = []; //hold the new merge array

let i = 0;

let j = 0; //keep track of the current position in the loop

while (i < arr1.length && j < arr2.length) {

if (arr2[j] > arr1[i]) {

result.push(arr1[i]);

i++;

} else {

result.push[arr2[j]];

j++;

}

}

// Push the leftover Array Element if arr1 and arr2 length not equal

while (i < arr1.length) {

result.push(arr1[i]);

i++;

}

while (j < arr2.length) {

result.push(arr2[j]);

j++;

}

return result;

};