Added easy/powers_of_two

bradhanson · bradhanson · commit 56a4976a0ac6 · 2018-08-03T18:24:33.000-04:00
diff --git a/easy/powers_of_two.js b/easy/powers_of_two.js
@@ -0,0 +1,17 @@
+/**
+ * Have the function powersOfTwo(num) take the num parameter being passed which
+ * will be an integer and return the string true if it's a power of two. If it's
+ * not return the string false. For example if the input is 16 then your program
+ * should return the string true but if the input is 22 then the output should
+ * be the string false.
+ *
+ * https://www.coderbyte.com/results/bhanson:Powers%20of%20Two:JavaScript
+ *
+ * @param  {number} num
+ * @return {string} 'true' or 'false'
+ */
+function powersOfTwo(num) {
+    return Number.isInteger(Math.log(num) / Math.log(2)) ? 'true' : 'false';
+}
+
+module.exports = powersOfTwo;
diff --git a/easy/powers_of_two.test.js b/easy/powers_of_two.test.js
@@ -0,0 +1,13 @@
+const powersOfTwo = require('./powers_of_two');
+
+describe('powersOfTwo()', () => {
+    test("returns 'true' for power of two", () => {
+        expect(powersOfTwo(16)).toBe('true');
+        expect(powersOfTwo(256)).toBe('true');
+    });
+
+    test("returns 'false' for not power of two", () => {
+        expect(powersOfTwo(22)).toBe('false');
+        expect(powersOfTwo(257)).toBe('false');
+    });
+});
