Prime numbers

Author: edignot

package-lock.json

@@ -1,5 +1,7 @@
 // Problem: return the nth element of the Fibonacci sequence
-// Fibonacci sequence: 1,1,2,3,5,8,13,21...
+// Details: e.g. fibonacci sequence: 1,1,2,3,5,8,13,21...
+
+// Time complexity: O(n)
 
 const getFibonacciEl = (i) => {
     const fibonacciArr = [1, 1];

src/fibonacci-sequence/fibonacci-sequence.js

@@ -0,0 +1,13 @@
+import isNumberPrime from "./primal-numbers";
+
+describe("Is 4 prime", () => {
+    test("2nd element of fibonacci sequence", () => {
+        expect(isNumberPrime(4)).toBe(false);
+    });
+    test("2nd element of fibonacci sequence", () => {
+        expect(isNumberPrime(17)).toBe(true);
+    });
+    test("2nd element of fibonacci sequence", () => {
+        expect(isNumberPrime(97)).toBe(true);
+    });
+});

src/pirmal-numbers/primal-number.test.js

@@ -0,0 +1,14 @@
+// Problem: Find if given number is a prime number or not. Return true or false
+// Details: Prime number can be divided by 1 or itself
+
+// Time complexity:
+
+const isNumberPrime = (num) => {
+    let isPrime = true;
+    for (let i = 2; i < num; i++) {
+        if (num % i === 0) isPrime = false;
+    }
+    return isPrime;
+};
+
+export default isNumberPrime;