Write a JavaScript Program to Display Fibonacci Sequence Using Recursion

The Fibonacci sequence is a series of numbers in which each number is the sum of the two preceding ones.

For example, the sequence goes 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, and so on.

It is a popular mathematical concept and can be implemented using recursion in JavaScript.

Recursion is a process in which a function calls itself repeatedly until a base condition is met.

In this case, the base condition will be the length of the sequence that we want to display.

Let’s take a look at how we can write a JavaScript program to display the Fibonacci sequence using recursion.

```function fibonacci(num) {
if (num <= 1) return [0, 1];
else {
var arr = fibonacci(num - 1);
arr.push(arr[arr.length - 1] + arr[arr.length - 2]);
return arr;
}
}

console.log(fibonacci(10));
```

In the above code, we define a function called fibonacci that takes in a parameter num, which represents the number of elements we want to display in the sequence.

We start with a base condition that checks whether num is less than or equal to 1.

If it is, we return an array with the values 0 and 1, which represent the first two numbers in the sequence.

If num is greater than 1, we call the fibonacci function recursively with num – 1.

This will continue until the base condition is met, at which point we start building the sequence.

We push the sum of the last two elements in the array to the end of the array, and then we return the array.

Finally, we log the output of fibonacci(10) to the console, which will display the first 10 numbers in the Fibonacci sequence: [0, 1, 1, 2, 3, 5, 8, 13, 21, 34].

In conclusion, the Fibonacci sequence is a popular mathematical concept that can be implemented using recursion in JavaScript.