Adding more details on how to run the playground code to address the issue trekhleb#705.

Author: trekhleb

src/playground/__test__/playground.test.js

@@ -1,5 +1,8 @@
+import playground from '../playground';
+
 describe('playground', () => {
-  it('should perform playground tasks', () => {
-    // Place your playground tests here.
+  it('should return correct results', () => {
+    // Replace the next dummy test with your playground function tests.
+    expect(playground()).toBe(120);
   });
 });

src/playground/playground.js

@@ -1 +1,12 @@
-// Place your playground code here.
+// Import any algorithmic dependencies you need for your playground code here.
+import factorial from '../algorithms/math/factorial/factorial';
+
+// Write your playground code inside the playground() function.
+// Test your code from __tests__/playground.test.js
+// Launch playground tests by running: npm test -- 'playground'
+function playground() {
+  // Replace the next line with your playground code.
+  return factorial(5);
+}
+
+export default playground;