wip: code formatting nits continued

test/isNumber.spec.js

@@ -0,0 +1,38 @@
+import lodashStable from 'lodash';
+import { falsey, args, slice, symbol, realm } from './utils';
+import isNumber from '../src/isNumber';
+
+describe('isNumber', () => {
+    it('should return `true` for numbers', () => {
+        expect(isNumber(0)).toBe(true);
+        expect(isNumber(Object(0))).toBe(true);
+        expect(isNumber(NaN)).toBe(true);
+    });
+
+    it('should return `false` for non-numbers', () => {
+        const expected = lodashStable.map(falsey, (value) => typeof value === 'number');
+
+        const actual = lodashStable.map(falsey, (value, index) =>
+            index ? isNumber(value) : isNumber(),
+        );
+
+        expect(actual).toEqual(expected);
+
+        expect(isNumber(args)).toBe(false);
+        expect(isNumber([1, 2, 3])).toBe(false);
+        expect(isNumber(true)).toBe(false);
+        expect(isNumber(new Date())).toBe(false);
+        expect(isNumber(new Error())).toBe(false);
+        expect(isNumber(slice)).toBe(false);
+        expect(isNumber({ a: 1 })).toBe(false);
+        expect(isNumber(/x/)).toBe(false);
+        expect(isNumber('a')).toBe(false);
+        expect(isNumber(symbol)).toBe(false);
+    });
+
+    it('should work with numbers from another realm', () => {
+        if (realm.number) {
+            expect(isNumber(realm.number)).toBe(true);
+        }
+    });
+});