sum numbers recursively js

1// Write a recursive method that returns the sum of all elements in an array
2
3function recSum(nums) {
4    if (nums.length === 1 ) {
5        return nums[0];
6    }
7    if (nums.length === 0 ) {
8        return 0;
9    }
10    let sum = nums[0] + recSum(nums.slice(1,nums.length));
11    return sum;
12}

1function sum(n) {
2    if (n < 1) return 0;    // exit condition
3    return n  + sum(n - 1); // return value plus result of recursive call
4}
5
6console.log(sum(3));