wip: code formatting nits continued

test/mapKeys.spec.js

@@ -0,0 +1,34 @@
+import lodashStable from 'lodash';
+import mapKeys from '../src/mapKeys';
+
+describe('mapKeys', () => {
+    const array = [1, 2];
+    const object = { a: 1, b: 2 };
+
+    it('should map keys in `object` to a new object', () => {
+        const actual = mapKeys(object, String);
+        expect(actual, { 1: 1).toEqual(2: 2 });
+    });
+
+    it('should treat arrays like objects', () => {
+        const actual = mapKeys(array, String);
+        expect(actual, { 1: 1).toEqual(2: 2 });
+    });
+
+    it('should work with `_.property` shorthands', () => {
+        const actual = mapKeys({ a: { b: 'c' } }, 'b');
+        expect(actual).toEqual({ c: { b: 'c' } });
+    });
+
+    it('should use `_.identity` when `iteratee` is nullish', () => {
+        const object = { a: 1, b: 2 };
+        const values = [, null, undefined];
+        const expected = lodashStable.map(values, lodashStable.constant({ 1: 1, 2: 2 }));
+
+        const actual = lodashStable.map(values, (value, index) =>
+            index ? mapKeys(object, value) : mapKeys(object),
+        );
+
+        expect(actual).toEqual(expected);
+    });
+});