Added dependency injection

src/backend/Injector/Injector.ts

@@ -0,0 +1,50 @@
+import 'reflect-metadata';
+import { Type } from './Util';
+import { FrontworkComponent } from '../Types/FrontworkComponent';
+
+
+/**
+ * The Injector stores services and resolves requested instances.
+ */
+export const Injector = new class {
+
+  injectionQueue :any[] = []
+
+  rootInterface : Type<any>
+  root : Type<any>
+  rootModules : Type<any>[] = []
+
+  moduleObjs : {[key in string] : FrontworkComponent} = {}
+
+  /**
+   * Resolves instances by injecting required services
+   * @param {Type<any>} target
+   * @returns {T}
+   */
+  resolve<T>(target: Type<any>): T {
+    // tokens are required dependencies, while injections are resolved tokens from the Injector
+
+    if(this.moduleObjs[target.name])
+      return this.moduleObjs[target.name] as any
+
+    if(target.name === this.rootInterface.name || target.name === this.root.name){
+      let modules = this.rootModules.map(m => {
+        const module = new m()
+        this.moduleObjs[m.name] = module
+        return module
+      })
+      const rootobj = new this.root(modules);
+
+      this.moduleObjs[this.rootInterface.name] = rootobj
+      this.moduleObjs[target.name] = rootobj
+      this.injectionQueue.forEach(i => {
+        i.target[i.where] = this.moduleObjs[i.what.name]
+      })
+      return rootobj
+    }
+    this.moduleObjs[target.name] = new target()
+    return this.moduleObjs[target.name] as any
+    
+    
+  }
+};

src/backend/Injector/ServiceDecorator.ts

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+import { Injector } from "./Injector";
+import { Type, GenericClassDecorator } from "./Util";
+import { FrontworkComponent } from "../Types/FrontworkComponent";
+
+/**
+ * @returns {GenericClassDecorator<Type<any>>}
+ * @constructor
+ */
+export const Module = (...args) : GenericClassDecorator<Type<any>> => {
+  return (target: Type<any>) => {
+    Injector.rootModules.push(target)
+  }
+}
+
+/**
+ * @returns {GenericClassDecorator<Type<any>>}
+ * @constructor
+ */
+export const RootComponent = (config : {
+    rootInterface : Type<any>
+    imports : Type<FrontworkComponent>[]
+  }) : GenericClassDecorator<Type<any>> => {
+  return (target: Type<any>) => {
+    Injector.rootModules = config.imports
+    Injector.rootInterface = config.rootInterface
+    Injector.root = target
+  }
+}
+
+export const Inject = (type: any) => {
+  return function (_this, key) {
+    Injector.injectionQueue.push({what: type, target: _this, where:key})
+  }
+}

src/backend/Injector/Util.ts

@@ -0,0 +1,11 @@
+/**
+ * Type for what object is instances of
+ */
+export interface Type<T> {
+  new(...args: any[]): T;
+}
+
+/**
+ * Generic `ClassDecorator` type
+ */
+export type GenericClassDecorator<T> = (target: T) => void;