JavaScript(JS) JS find sum of natural numbers using recursion

To find the sum of the first n natural numbers using recursion in JavaScript, you can use the following code:

function sum(n) {
  if (n <= 1) {
    return n;
  } else {
    return n + sum(n - 1);
  }
}

// Example usage
console.log(sum(5)); // Output: 15

In this example, the sum function takes a single argument n, which represents the number of natural numbers to add together. If n is less than or equal to 1, the function returns n (which represents the sum of the numbers). If n is greater than 1, the function returns n plus the sum of the first n - 1 natural numbers (which is calculated recursively by calling the sum function with an argument of n - 1). This process continues until the base case is reached (when n is 1 or less), at which point the final sum is returned.