adding support demo and exercise sub dirs

step2-01/src/async/index.ts

@@ -7,3 +7,6 @@ async function fetchSomething() {
 fetchSomething().then(text => {
   console.log('hello ' + text);
 });
+
+// adding an export to turn this into a "module"
+export default {};

step2-01/src/generics/index.ts

@@ -18,3 +18,6 @@ function reverse<T>(arg: T[]): T[] {
   // TODO: implement the logic to reverse the array
   return arg;
 }
+
+// adding an export to turn this into a "module"
+export default {};

step2-01/src/interfaces/index.ts

@@ -17,3 +17,6 @@ const myCar: Car = {
 interface InterestingFn {
   (someArgs: string): number;
 }
+
+// adding an export to turn this into a "module"
+export default {};

step2-01/src/spread/index.ts

@@ -10,3 +10,6 @@ console.log(list); // [1,2,3,4]
 // Object assignment
 const point2D = { x: 1, y: 2 };
 const point3D = { ...point2D, z: 3 };
+
+// adding an export to turn this into a "module"
+export default {};

step2-01/src/types/index.ts

@@ -50,3 +50,6 @@ class Animal {}
 // noted exception: React.Component with react@<16.8.0
 class Cat extends Animal {}
 class Dog extends Animal {}
+
+// adding an export to turn this into a "module"
+export default {};