prototypes

Author: a.shatalov

prototype/PrototypeExample.js

@@ -0,0 +1,15 @@
+export function Dog(name) {
+  this.name = name;
+}
+
+Dog.prototype.bark = () => console.log('bark');
+
+export function Pug(name) {
+  Dog.call(this, name);
+}
+
+Pug.prototype = Object.create(Dog.prototype);
+Pug.prototype.constructor = Pug;
+
+
+export const atomThePug = new Pug('atom');

prototype/PrototypeExample.test.js

@@ -0,0 +1,19 @@
+import { atomThePug, Dog, Pug } from './PrototypeExample';
+describe('atomThePug', () => {
+  test('properties', () => {
+    expect(atomThePug.name).toBe('atom');
+    expect(atomThePug.bark).toEqual(expect.any(Function));
+  });
+  test('constructor', () => {
+    expect(atomThePug.constructor).toEqual(Pug);
+    expect(atomThePug.constructor).not.toEqual(Dog);
+  });
+  test('instanceof', () => {
+    expect(atomThePug instanceof Pug).toBeTruthy();
+    expect(atomThePug instanceof Dog).toBeTruthy();
+  });
+  test('hasOwnProperty', () => {
+    expect(atomThePug.hasOwnProperty('bark')).toBeFalsy();
+    expect(atomThePug.hasOwnProperty('name')).toBeTruthy();
+  });
+});