adding fibonacci nth

Author: Jero786

README.md

@@ -104,6 +104,7 @@
 1. [Product Array Except Self](/product-array-except-self/index.test.js)
 1. [Best time to Buy and Sell](/best-time-to-buy-and-sell/index.test.js)
 1. [Tandem Bicycle](/tandem-bicycle/index.test.js)
+1. [Nth Fibonacci](/nth-fibonacci/index.test.js)
 
 ## Setup
 

nth-fibonacci/index.js

@@ -0,0 +1,23 @@
+function fibonacciNthRecursively(number, fibonacci = [0, 1], i = 2) {
+    if (i > number) {
+        return fibonacci[number - 1];
+    } else {
+        fibonacci.push(fibonacci[i - 1] + fibonacci[i - 2]);
+        return fibonacciNthRecursively(number, fibonacci, i + 1);
+    }
+}
+
+function fibonacciNth(number) {
+    let numbers = [0, 1];
+
+    for (let i = 2; i <= number; i++) {
+        numbers.push(numbers[i - 1] + numbers[i - 2]);
+    }
+
+    return numbers[number - 1] ;
+}
+
+module.exports = {
+    fibonacciNthRecursively,
+    fibonacciNth
+}

nth-fibonacci/index.test.js

@@ -0,0 +1,26 @@
+const { fibonacciNthRecursively, fibonacciNth } = require('.');
+
+describe('Nth Fibonacci', () => {
+    describe('recursively', () => {
+           test.each([
+            [1, 0],
+            [3, 1],
+            [2, 1],
+            [6, 5],
+        ])('with %i',(input, expected) => {
+           const result = fibonacciNthRecursively(input);
+            expect(result).toEqual(expected); 
+        })
+    });
+    describe('iteratily', () => {
+        test.each([
+            [1, 0],
+            [3, 1],
+            [2, 1],
+            [6, 5],
+        ])('with %i',(input, expected) => {
+           const result = fibonacciNth(input);
+            expect(result).toEqual(expected); 
+        })
+    });
+});