wip: code formatting nits continued

test/isNil.spec.js

@@ -0,0 +1,41 @@
+import lodashStable from 'lodash';
+import { falsey, args, slice, symbol, realm } from './utils';
+import isNil from '../src/isNil';
+
+describe('isNil', () => {
+    it('should return `true` for nullish values', () => {
+        expect(isNil(null)).toBe(true);
+        expect(isNil()).toBe(true);
+        expect(isNil(undefined)).toBe(true);
+    });
+
+    it('should return `false` for non-nullish values', () => {
+        const expected = lodashStable.map(falsey, (value) => value === null);
+
+        const actual = lodashStable.map(falsey, (value, index) => (index ? isNil(value) : isNil()));
+
+        expect(actual).toEqual(expected);
+
+        expect(isNil(args)).toBe(false);
+        expect(isNil([1, 2, 3])).toBe(false);
+        expect(isNil(true)).toBe(false);
+        expect(isNil(new Date())).toBe(false);
+        expect(isNil(new Error())).toBe(false);
+        expect(isNil(slice)).toBe(false);
+        expect(isNil({ a: 1 })).toBe(false);
+        expect(isNil(1)).toBe(false);
+        expect(isNil(/x/)).toBe(false);
+        expect(isNil('a')).toBe(false);
+
+        if (Symbol) {
+            expect(isNil(symbol)).toBe(false);
+        }
+    });
+
+    it('should work with nils from another realm', () => {
+        if (realm.object) {
+            expect(isNil(realm.null)).toBe(true);
+            expect(isNil(realm.undefined)).toBe(true);
+        }
+    });
+});