From 600d671b804c791ae9934d35994ca058175d60eb Mon Sep 17 00:00:00 2001
From: htoopyae <htoopyae5@gmail.com>
Date: Tue, 16 Oct 2018 11:01:46 +0630
Subject: [PATCH] Math:Fibonacci Added

---
 src/algorithms/math/fibonacci.js      | 25 +++++++++++++++++++++++++
 src/algorithms/math/index.js          |  4 +++-
 test/algorithms/math/testFibonacci.js | 22 ++++++++++++++++++++++
 3 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 src/algorithms/math/fibonacci.js
 create mode 100644 test/algorithms/math/testFibonacci.js

diff --git a/src/algorithms/math/fibonacci.js b/src/algorithms/math/fibonacci.js
new file mode 100644
index 00000000..117633bf
--- /dev/null
+++ b/src/algorithms/math/fibonacci.js
@@ -0,0 +1,25 @@
+/**
+ * Show fibonacci sequence up to a given number
+ * @param {Number} num given number
+ */
+const fibonacci = (num) => {
+  let n1 = 0;
+  let n2 = 1;
+  const fibo = [];
+
+  if (num < 0) {
+    throw new Error('Not a positive number');
+  }
+
+  while (n1 <= num) {
+    fibo.push(n1);
+
+    const sum = n1 + n2;
+    n1 = n2;
+    n2 = sum;
+  }
+
+  return fibo;
+};
+
+module.exports = fibonacci;
diff --git a/src/algorithms/math/index.js b/src/algorithms/math/index.js
index 41b2e488..25a8bcea 100644
--- a/src/algorithms/math/index.js
+++ b/src/algorithms/math/index.js
@@ -3,11 +3,13 @@ const gcd = require('./gcd');
 const fastexp = require('./fast_exp');
 const lcm = require('./lcm');
 const modularInverse = require('./modular_inverse');
+const fibonacci = require('./fibonacci');
 
 module.exports = {
   extendedEuclidean,
   gcd,
   fastexp,
   lcm,
-  modularInverse
+  modularInverse,
+  fibonacci
 };
diff --git a/test/algorithms/math/testFibonacci.js b/test/algorithms/math/testFibonacci.js
new file mode 100644
index 00000000..d216f7fb
--- /dev/null
+++ b/test/algorithms/math/testFibonacci.js
@@ -0,0 +1,22 @@
+/* eslint-env mocha */
+const fibonacci = require('../../../src/algorithms/math/fibonacci');
+
+const assert = require('assert');
+
+describe('Fibonacci', () => {
+  it('should return 0 if given number is 0', () => {
+    assert.deepStrictEqual(fibonacci(0), [0]);
+  });
+
+  it('should throw an error if the number is negative', () => {
+    assert.throws(() => fibonacci(-5));
+  });
+
+  it('should return fibonacci sequence up to 10', () => {
+    assert.deepStrictEqual(fibonacci(10), [0, 1, 1, 2, 3, 5, 8]);
+  });
+
+  it('should return fibonacci sequence up to 100', () => {
+    assert.deepStrictEqual(fibonacci(100), [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]);
+  });
+});