Adding a system.js module

src/app.ts

@@ -1,6 +1,7 @@
 import { ICounter } from "./common/interfaces";
 import { CommonJsCounter } from "./commonjs/module1";
-import { AmdCounter } from "./amd/module2"
+import { AmdCounter } from "./amd/module2";
+import { SystemJsCounter } from "./systemjs/module3";
 
 const testCounter = (counter: ICounter) => {
     counter.incr();
@@ -10,4 +11,5 @@ const testCounter = (counter: ICounter) => {
 }
 
 testCounter(new CommonJsCounter(5));
-testCounter(new AmdCounter(10));
+testCounter(new AmdCounter(10));
+testCounter(new SystemJsCounter(15));

src/systemjs/module3.ts

@@ -0,0 +1,18 @@
+import { ICounter } from "../common/interfaces";
+
+export class SystemJsCounter implements ICounter {
+    constructor(private _value:number = 0) {
+    }
+
+    public get value(): string {
+        return `esm ${this._value}`;
+    }
+
+    public incr(): void {
+        ++this._value;
+    }
+
+    public decr(): void {
+        --this._value;
+    }
+}