From 6ddb90e8e2e33719586bf6fe8f826aade88a4278 Mon Sep 17 00:00:00 2001
From: Niels Kooiman <niels.kooiman@gmail.com>
Date: Mon, 26 Feb 2018 13:05:32 +0100
Subject: [PATCH] Injector Example

---
 src/domain/ports/IInjector.ts              |  3 +++
 src/domain/services/MusicCatalogService.ts |  8 +++++++-
 src/view/MusicComponent.ts                 | 23 +++++++---------------
 src/wiring/Wiring.ts                       | 20 +++++++++++++++++++
 4 files changed, 37 insertions(+), 17 deletions(-)
 create mode 100644 src/domain/ports/IInjector.ts
 create mode 100644 src/wiring/Wiring.ts

diff --git a/src/domain/ports/IInjector.ts b/src/domain/ports/IInjector.ts
new file mode 100644
index 0000000..2a32354
--- /dev/null
+++ b/src/domain/ports/IInjector.ts
@@ -0,0 +1,3 @@
+export interface IInjector {
+    inject<T>(name : string) : T;
+}
diff --git a/src/domain/services/MusicCatalogService.ts b/src/domain/services/MusicCatalogService.ts
index 37c0d72..79d17cb 100644
--- a/src/domain/services/MusicCatalogService.ts
+++ b/src/domain/services/MusicCatalogService.ts
@@ -1,12 +1,18 @@
 import { IMusicRepository } from "../../domain/ports/IMusicRepository";
 import { Track } from "../../domain/models/Track";
+import { IInjector } from "../../domain/ports/IInjector";
+
 
 
 export class MusicCatalogService {
     private repository: IMusicRepository;
 
     constructor(repository:IMusicRepository){
-        this.repository= repository;
+        this.repository = repository;
+    }
+
+    static new(injector : IInjector) : MusicCatalogService {
+        return new MusicCatalogService(injector.inject<IMusicRepository>("IMusicRepository"))
     }
 
     get(): Track[] {
diff --git a/src/view/MusicComponent.ts b/src/view/MusicComponent.ts
index b003dc3..5d66596 100644
--- a/src/view/MusicComponent.ts
+++ b/src/view/MusicComponent.ts
@@ -4,29 +4,20 @@ import { IMusicRepository } from "../domain/ports/IMusicRepository";
 import { Track } from "../domain/models/Track";
 import { VinylCatalog } from "../adapters/music/VinylCatalog";
 
+import { Wiring } from "../wiring/Wiring";
+
 export class MusicComponent {
     constructor() {
 
-        let container : any = { };
-
-        let register = (name : string, fn : Function) => {
-            container[name] = fn;
-        };
-
-        let inject = (name : string) : any => {
-            if (container[name]) {
-                return container[name]();
-            }
-            throw new Error(`Failed to resolve ${name}`)
-        };
-
         console.log('registering IMusicRepository');
-        register('IMusicRepository', () => new VinylCatalog());
+        Wiring.register('IMusicRepository', () => new VinylCatalog());
 
-        let musicRepository = inject("IMusicRepository") as IMusicRepository;
+        var injector = Wiring.GetInjector();
+        let musicRepository = injector.inject<IMusicRepository>("IMusicRepository");
         console.log('IMusicRepository is', musicRepository);
 
-        let musicCatalogService = new MusicCatalogService(musicRepository);
+        //let musicCatalogService = new MusicCatalogService(injector.inject<IMusicRepository>("IMusicRepository"));
+        let musicCatalogService = MusicCatalogService.new(injector);
 
         let track = new Track(8, "Niels 1st", "Niels Kooiman", 45);
         musicCatalogService.add(track);
diff --git a/src/wiring/Wiring.ts b/src/wiring/Wiring.ts
new file mode 100644
index 0000000..f59655c
--- /dev/null
+++ b/src/wiring/Wiring.ts
@@ -0,0 +1,20 @@
+
+import { IInjector } from "../domain/ports/IInjector"
+
+export class Wiring implements IInjector {
+    private static container : any = { };
+    public static register(name : string, fn : Function) : void {
+        Wiring.container[name] = fn;
+    };
+
+    public static GetInjector() : IInjector {
+        return new Wiring();
+    }
+
+    public inject = function<T>(name : string) : T {
+        if (Wiring.container[name]) {
+            return Wiring.container[name]();
+        }
+        throw new Error(`Failed to resolve ${name}`)
+    };
+};