### Fibonacci Program in JavaScript

In this post, we will learn three different ways to find the Fibonacci of given number using JavaScript.
The Fibonacci sequence can be defined as follows:
• The Fibonacci sequence of 1 or 2 is 1
• The Fibonacci sequence of n (for n>2) is the Fibonacci of (n-1) + Fibonacci of (n-2)

# Using Recursive

```function fibonacci(n) {
if (n < 1) {
return 0;
}
if (n <= 2) {
return 1;
}
return fibonacci(n - 1) + fibonacci(n - 2);
}

console.log("fibonacci -> " + fibonacci(6));```
Output:
``fibonacci -> 8``

# Using Iterative

```function fibonacciIterative(n) {
if (n < 1) {
return 0;
}
let fibNMinus2 = 0;
let fibNMinus1 = 1;
let fibN = n;
for (let i = 2; i <= n; i++) {
fibN = fibNMinus1 + fibNMinus2;
fibNMinus2 = fibNMinus1;
fibNMinus1 = fibN;
}
return fibN;
}

console.log(" fibonacci Iterative -> " + fibonacci(6));```
Output:
``fibonacci Iterative -> 8``

# Using Memoization

```function fibonacciMemoization(n) {
if (n < 1) {
return 0;
}
const memo = [0, 1];
const fibonacciMem = num => {
if (memo[num] != null) {
return memo[num];
}
return (memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2));
};
return fibonacciMem(n);
}

console.log(" fibonacci Memoization ->  " + fibonacci(6));```
Output:
``fibonacci Memoization ->  8``

# Free Spring Boot Tutorial | Full In-depth Course | Learn Spring Boot in 10 Hours

Watch this course on YouTube at Spring Boot Tutorial | Fee 10 Hours Full Course