Recursive Staircase problem in JavaScript

Suppose we have the following problem −

There are n stairs, a person standing at the bottom wants to reach the top. The person can climb either 1 or 2 stairs at a time. We are required to count the number of ways, the person can reach the top.

We are required to write a JavaScript function that takes in a number n that denotes the number of stairs. The function should count and return the number of ways in which the stairs can be climbed.

Example

Following is the code −

const recursiveStaircase = (num = 10) => {
   if (num 
Output
Following is the output on console −
89
5
377