Added easy/swap_case

bradhanson · bradhanson · commit 0963da84e967 · 2018-07-29T11:02:26.000-07:00
diff --git a/easy/swap_case.js b/easy/swap_case.js
@@ -0,0 +1,33 @@
+/**
+ * Have the function swapCase(str) take the str parameter and swap the case of
+ * each character. For example: if str is "Hello World" the output should be
+ * hELLO wORLD. Let numbers and symbols stay the way they are.
+ *
+ * https://www.coderbyte.com/results/bhanson:Swap%20Case:JavaScript
+ *
+ * @param  {string} str
+ * @return {string}
+ */
+function swapCase(str) {
+    const LOWER = 'abcdefghijklmnopqrstuvwxyz';
+    const UPPER = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
+
+    const newString = str
+        .split('')
+        .map(char => {
+            if (LOWER.includes(char)) {
+                return char.toUpperCase();
+            }
+
+            if (UPPER.includes(char)) {
+                return char.toLowerCase();
+            }
+
+            return char;
+        })
+        .join('');
+
+    return newString;
+}
+
+module.exports = swapCase;
diff --git a/easy/swap_case.test.js b/easy/swap_case.test.js
@@ -0,0 +1,21 @@
+const swapCase = require('./swap_case');
+
+describe('swapCase()', () => {
+    test('converts lowercase letters to uppercase', () => {
+        expect(swapCase('abcz')).toBe('ABCZ');
+    });
+
+    test('converts uppercase letters to lowercase', () => {
+        expect(swapCase('ZABC')).toBe('zabc');
+    });
+
+    test('correctly swaps cases', () => {
+        expect(swapCase('the QUICK Brown foX')).toBe('THE quick bROWN FOx');
+    });
+
+    test('ignores non alphabetic characters', () => {
+        expect(swapCase('the $&@!QUICK &@!Brown&@! foX')).toBe(
+            'THE $&@!quick &@!bROWN&@! FOx'
+        );
+    });
+});
