Merge and Sort two arrays into one with O(n) runtime in Javascript without Concat() or sort()

Given two sorted Arrays Arr1 and Arr2, merge Arr2 into Arr1 as a sorted array.You can assume that Arr1 has enough space to hold additional elements from Arr2. The number of elements in Arr1 and Arr2 are m and n respectively.

#array #mergearrays #onruntime #twoarraysintoone #null #javascript #datastructure #nosort