revert changes, according to PR

test/deepMapKeys.test.js

@@ -0,0 +1,32 @@
+const expect = require('expect');
+const { deepMapKeys, toCamelCase } = require('./_30s.js');
+
+test('deepMapKeys is a Function', () => {
+  expect(deepMapKeys).toBeInstanceOf(Function);
+});
+
+test('Deep maps object keys', () => {
+  const obj = {
+    'foo_bar': 'hello',
+    'deep_child': {
+      'child_array': ['hello'],
+      'child_object_array': [
+        { 'hola_hello': 'Gamarjoba' }
+      ]
+    }
+  };
+  const expected = {
+    fooBar: 'hello',
+    deepChild: {
+      childArray: ['hello'],
+      childObjectArray: [
+        {
+          holaHello: 'Gamarjoba'
+        }
+      ]
+    }
+  };
+  const camleCaseKeys = k => toCamelCase(k);
+  expect(deepMapKeys(obj, camleCaseKeys)).toEqual(expected);
+});
+