Merging sorted arrays together JavaScript

Suppose we have two sorted arrays (increasing order) like this −

const arr1 = [1, 2, 3, 0, 0, 0];
const arr2 = [2, 5, 6];

We are required to write a JavaScript function that takes in two such arrays and returns a new array that contains all the elements from these arrays in a sorted manner.

Therefore, for the above arrays, the output should look like −

const output = [1, 2, 2, 3, 5, 6];

Example

const arr1 = [1, 2, 3, 0, 0, 0];
const arr2 = [2, 5, 6];
const mergeSortedArrays = (arr1, arr2) => {
   let { length: l1 } = arr1;
   let { length: l2 } = arr2;
   while(l2){
      arr1[l1++] = arr2[--l2];
   };
   const sorter = (a, b) => a - b;
   arr1.sort(sorter);
};
mergeSortedArrays(arr1, arr2);
console.log(arr1);

Output

And the output in the console will be −

[
   0, 0, 0, 1, 2,
   2, 3, 5, 6
]