TypeScript Decorators: Mestring af Metadata-programmeringsmønstre for Robuste Applikationer

            @MyDecorator\nclass MyClass {\n  @AnotherDecorator\n  myMethod() {\n    // ...\n  }\n}
            

              
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            // tsconfig.json\n{\n  "compilerOptions": {\n    "target": "ES2017",\n    "module": "commonjs",\n    "experimentalDecorators": true,\n    "emitDecoratorMetadata": true,\n    "outDir": "./dist",\n    "strict": true,\n    "esModuleInterop": true,\n    "skipLibCheck": true,\n    "forceConsistentCasingInFileNames": true\n  }\n}
            

              
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            npm install reflect-metadata --save\n# or\nyarn add reflect-metadata
            

              
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            import "reflect-metadata";\n// Din applikationskode følger
            

              
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            function Logger(prefix: string) {\n  return function (target: Function) {\n    console.log(`[${prefix}] Klassen ${target.name} er blevet defineret.`);\n  };\n}\n\n@Logger("APP_INIT")\nclass ApplicationBootstrap {\n  constructor() {\n    console.log("Applikationen starter...");\n  }\n}\n\nconst app = new ApplicationBootstrap();\n// Output:\n// [APP_INIT] Klassen ApplicationBootstrap er blevet defineret.\n// Applikationen starter...
            

              
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            function ClassDecorator(target: Function) { ... }
            

              
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            const InjectableServiceRegistry = new Map<string, Function>();\n\nfunction Injectable(name?: string) {\n  return function<T extends { new(...args: any[]): {} }>(constructor: T) {\n    const serviceName = name || constructor.name;\n    InjectableServiceRegistry.set(serviceName, constructor);\n    console.log(`Registreret service: ${serviceName}`);\n\n    // Valgfrit kan du returnere en ny klasse her for at udvide funktionaliteten\n    return class extends constructor {\n      createdAt = new Date();\n      // Yderligere properties eller metoder for alle injicerede services\n    };\n  };\n}\n\n@Injectable("UserService")\nclass UserDataService {\n  getUsers() {\n    return [{ id: 1, name: "Alice" }, { id: 2, name: "Bob" }];\n  }\n}\n\n@Injectable()\nclass ProductDataService {\n  getProducts() {\n    return [{ id: 101, name: "Laptop" }, { id: 102, name: "Mouse" }];\n  }\n}\n\nconsole.log("--- Services Registreret ---");\nconsole.log(Array.from(InjectableServiceRegistry.keys()));\n\nconst userServiceConstructor = InjectableServiceRegistry.get("UserService");\nif (userServiceConstructor) {\n  const userServiceInstance = new userServiceConstructor();\n  console.log("Brugere:", userServiceInstance.getUsers());\n  // console.log("User Service oprettet den:", userServiceInstance.createdAt); // Hvis den returnerede klasse bruges\n}
            

              
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            function MethodDecorator(target: Object, propertyKey: string | symbol, descriptor: PropertyDescriptor) { ... }
            

              
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            function MeasurePerformance(target: Object, propertyKey: string, descriptor: PropertyDescriptor) {\n  const originalMethod = descriptor.value;\n\n  descriptor.value = function(...args: any[]) {\n    const start = process.hrtime.bigint();\n    const result = originalMethod.apply(this, args);\n    const end = process.hrtime.bigint();\n    const duration = Number(end - start) / 1_000_000;\n    console.log(`Metoden \"${propertyKey}\" blev udført på ${duration.toFixed(2)} ms`);\n    return result;\n  };\n\n  return descriptor;\n}\n\nclass DataProcessor {\n  @MeasurePerformance\n  processData(data: number[]): number[] {\n    // Simulerer en kompleks, tidskrævende operation\n    for (let i = 0; i < 1_000_000; i++) {\n      Math.sin(i);\n    }\n    return data.map(n => n * 2);\n  }\n\n  @MeasurePerformance\n  fetchRemoteData(id: string): Promise<string> {\n    return new Promise(resolve => {\n      setTimeout(() => {\n        resolve(`Data for ID: ${id}`);\n      }, 500);\n    });\n  }\n}\n\nconst processor = new DataProcessor();\nprocessor.processData([1, 2, 3]);\nprocessor.fetchRemoteData("abc").then(result => console.log(result));
            

              
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            function AccessorDecorator(target: Object, propertyKey: string | symbol, descriptor: PropertyDescriptor) { ... }
            

              
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            function CachedGetter(target: any, propertyKey: string, descriptor: PropertyDescriptor) {\n  const originalGetter = descriptor.get;\n  const cacheKey = `_cached_${String(propertyKey)}`;\n\n  if (originalGetter) {\n    descriptor.get = function() {\n      if (this[cacheKey] === undefined) {\n        console.log(`[Cache Miss] Beregner værdi for ${String(propertyKey)}`);\n        this[cacheKey] = originalGetter.apply(this);\n      } else {\n        console.log(`[Cache Hit] Bruger cachet værdi for ${String(propertyKey)}`);\n      }\n      return this[cacheKey];\n    };\n  }\n  return descriptor;\n}\n\nclass ReportGenerator {\n  private data: number[];\n\n  constructor(data: number[]) {\n    this.data = data;\n  }\n\n  // Simulerer en dyr beregning\n  @CachedGetter\n  get expensiveSummary(): number {\n    console.log("Udfører dyr opsummeringsberegning...");\n    return this.data.reduce((sum, current) => sum + current, 0) / this.data.length;\n  }\n}\n\nconst generator = new ReportGenerator([10, 20, 30, 40, 50]);\n\nconsole.log("Første adgang:", generator.expensiveSummary);\nconsole.log("Anden adgang:", generator.expensiveSummary);\nconsole.log("Tredje adgang:", generator.expensiveSummary);
            

              
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            function PropertyDecorator(target: Object, propertyKey: string | symbol) { ... }
            

              
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            interface ValidationRule {\n  property: string | symbol;\n  validate: (value: any) => boolean;\n  message: string;\n}\n\nconst validationRules: Map<Function, ValidationRule[]> = new Map();\n\nfunction Required(target: Object, propertyKey: string | symbol) {\n  const rules = validationRules.get(target.constructor) || [];\n  rules.push({\n    property: propertyKey,\n    validate: (value: any) => value !== null && value !== undefined && value !== "",\n    message: `${String(propertyKey)} er påkrævet.`\n  });\n  validationRules.set(target.constructor, rules);\n}\n\nfunction validate(instance: any): string[] {\n  const classRules = validationRules.get(instance.constructor) || [];\n  const errors: string[] = [];\n\n  for (const rule of classRules) {\n    if (!rule.validate(instance[rule.property])) {\n      errors.push(rule.message);\n    }\n  }\n  return errors;\n}\n\nclass UserProfile {\n  @Required\n  firstName: string;\n\n  @Required\n  lastName: string;\n\n  age?: number;\n\n  constructor(firstName: string, lastName: string, age?: number) {\n    this.firstName = firstName;\n    this.lastName = lastName;\n    this.age = age;\n  }\n}\n\nconst user1 = new UserProfile("John", "Doe", 30);\nconsole.log("Valideringsfejl for Bruger 1:", validate(user1)); // []\n\nconst user2 = new UserProfile("", "Smith");\nconsole.log("Valideringsfejl for Bruger 2:", validate(user2)); // [\"firstName er påkrævet.\"]\n\nconst user3 = new UserProfile("Alice", "");\nconsole.log("Valideringsfejl for Bruger 3:", validate(user3)); // [\"lastName er påkrævet.\"]
            

              
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            function ParameterDecorator(target: Object, propertyKey: string | symbol | undefined, parameterIndex: number) { ... }
            

              
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            interface ParameterMetadata {\n  index: number;\n  key: string | symbol;\n  resolver: (request: any) => any;\n}\n\nconst parameterResolvers: Map<Function, Map<string | symbol, ParameterMetadata[]>> = new Map();\n\nfunction RequestParam(paramName: string) {\n  return function (target: Object, propertyKey: string | symbol | undefined, parameterIndex: number) {\n    const targetKey = propertyKey || "constructor";\n    let methodResolvers = parameterResolvers.get(target.constructor);\n    if (!methodResolvers) {\n      methodResolvers = new Map();\n      parameterResolvers.set(target.constructor, methodResolvers);\n    }\n    const paramMetadata = methodResolvers.get(targetKey) || [];\n    paramMetadata.push({\n      index: parameterIndex,\n      key: targetKey,\n      resolver: (request: any) => request[paramName]\n    });\n    methodResolvers.set(targetKey, paramMetadata);\n  };\n}\n\n// En hypotetisk framework-funktion til at kalde en metode med resolvede parametre\nfunction executeWithParams(instance: any, methodName: string, request: any) {\n  const classResolvers = parameterResolvers.get(instance.constructor);\n  if (!classResolvers) {\n    return (instance[methodName] as Function).apply(instance, []);\n  }\n  const methodParamMetadata = classResolvers.get(methodName);\n  if (!methodParamMetadata) {\n    return (instance[methodName] as Function).apply(instance, []);\n  }\n\n  const args: any[] = Array(methodParamMetadata.length);\n  for (const meta of methodParamMetadata) {\n    args[meta.index] = meta.resolver(request);\n  }\n  return (instance[methodName] as Function).apply(instance, args);\n}\n\nclass UserController {\n  getUser(@RequestParam("id") userId: string, @RequestParam("token") authToken?: string) {\n    console.log(`Henter bruger med ID: ${userId}, Token: ${authToken || \"N/A\"}`);\n    return { id: userId, name: "Jane Doe" };\n  }\n\n  deleteUser(@RequestParam("id") userId: string) {\n    console.log(`Sletter bruger med ID: ${userId}`);\n    return { status: "slettet", id: userId };\n  }\n}\n\nconst userController = new UserController();\n\n// Simulerer en indkommende anmodning\nconst mockRequest = {\n  id: "user123",\n  token: "abc-123",\n  someOtherProp: "xyz"\n};\n\nconsole.log("\n--- Udfører getUser ---");\nexecuteWithParams(userController, "getUser", mockRequest);\n\nconsole.log("\n--- Udfører deleteUser ---");\nexecuteWithParams(userController, "deleteUser", { id: "user456" });
            

              
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            @DecoratorA\n@DecoratorB\nclass MyClass {\n  // ...\n}\n
            

              
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            function LogCall(target: any, propertyKey: string, descriptor: PropertyDescriptor) {\n  const originalMethod = descriptor.value;\n  descriptor.value = function (...args: any[]) {\n    console.log(`[LOG] Kalder ${String(propertyKey)} med args:`, args);\n    const result = originalMethod.apply(this, args);\n    console.log(`[LOG] Metode ${String(propertyKey)} returnerede:`, result);\n    return result;\n  };\n  return descriptor;\n}\n\nfunction Authorization(roles: string[]) {\n  return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {\n    const originalMethod = descriptor.value;\n    descriptor.value = function (...args: any[]) {\n      const currentUserRoles = ["admin"]; // Simulerer hentning af nuværende brugerroller\n      const authorized = roles.some(role => currentUserRoles.includes(role));\n      if (!authorized) {\n        console.warn(`[AUTH] Adgang nægtet for ${String(propertyKey)}. Krævede roller: ${roles.join(", ")}`);\n        throw new Error("Uautoriseret adgang");\n      }\n      console.log(`[AUTH] Adgang givet for ${String(propertyKey)}`);\n      return originalMethod.apply(this, args);\n    };\n    return descriptor;\n  };\n}\n\nclass SecureService {\n  @LogCall\n  @Authorization(["admin"])\n  deleteSensitiveData(id: string) {\n    console.log(`Sletter følsomme data for ID: ${id}`);\n    return `Data ID ${id} slettet.`;\n  }\n\n  @Authorization(["user"])\n  @LogCall // Rækkefølge ændret her\n  fetchPublicData(query: string) {\n    console.log(`Henter offentlige data med forespørgsel: ${query}`);\n    return `Offentlige data for forespørgsel: ${query}`; \n  }\n}\n\nconst service = new SecureService();\n\ntry {\n  console.log("\n--- Kalder deleteSensitiveData (Admin Bruger) ---");\n  service.deleteSensitiveData("record123");\n} catch (error: any) {\n  console.error(error.message);\n}\n\ntry {\n  console.log("\n--- Kalder fetchPublicData (Ikke-Admin Bruger) ---");\n  // Simulerer en ikke-admin bruger, der forsøger at tilgå fetchPublicData, som kræver 'user'-rollen\n  const mockUserRoles = ["guest"]; // Dette vil fejle auth\n  // For at gøre dette dynamisk, ville du have brug for et DI-system eller statisk kontekst for nuværende brugerroller.\n  // For enkelthedens skyld antager vi, at Authorization-decoratoren har adgang til nuværende brugerkontekst.\n  // Lad os justere Authorization-decoratoren til altid at antage 'admin' for demoformål, \n  // så det første kald lykkes, og det andet fejler for at vise forskellige stier.\n  \n  // Kør igen med brugerrolle, for at fetchPublicData lykkes.\n  // Forestil dig, at currentUserRoles i Authorization bliver: ['user']\n  // For dette eksempel, lad os holde det simpelt og vise rækkefølgeeffekten.\n  service.fetchPublicData("søgeterm"); // Dette vil udføre Auth -> Log\n} catch (error: any) {\n  console.error(error.message);\n}\n\n/* Forventet output for deleteSensitiveData:\n[AUTH] Adgang givet for deleteSensitiveData\n[LOG] Kalder deleteSensitiveData med args: [ 'record123' ]\nSletter følsomme data for ID: record123\n[LOG] Metode deleteSensitiveData returnerede: Data ID record123 slettet.\n*/\n\n/* Forventet output for fetchPublicData (hvis bruger har 'user'-rollen):\n[LOG] Kalder fetchPublicData med args: [ 'søgeterm' ]\n[AUTH] Adgang givet for fetchPublicData\nHenter offentlige data med forespørgsel: søgeterm\n[LOG] Metode fetchPublicData returnerede: Offentlige data for forespørgsel: søgeterm\n*/
            

              
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            function log(message: string) {\n  return function (target: any, propertyKey: string | symbol | undefined, descriptorOrIndex?: PropertyDescriptor | number) {\n    if (typeof descriptorOrIndex === 'number') {\n      console.log(`Param Decorator: ${message} på parameter #${descriptorOrIndex} af ${String(propertyKey || \"constructor\")}`);\n    } else if (typeof propertyKey === 'string' || typeof propertyKey === 'symbol') {\n      if (descriptorOrIndex && 'value' in descriptorOrIndex && typeof descriptorOrIndex.value === 'function') {\n        console.log(`Metode/Accessor Decorator: ${message} på ${String(propertyKey)}`);\n      } else {\n        console.log(`Property Decorator: ${message} på ${String(propertyKey)}`);\n      }\n    } else {\n      console.log(`Klasse Decorator: ${message} på ${target.name}`);\n    }\n    return descriptorOrIndex; // Returner descriptor for metode/accessor, undefined for andre\n  };\n}\n\n@log("Klasse Niveau D")\n@log("Klasse Niveau C")\nclass MyDecoratedClass {\n  @log("Statisk Property A")\n  static staticProp: string = "";\n\n  @log("Instans Property B")\n  instanceProp: number = 0;\n\n  @log("Metode D")\n  @log("Metode C")\n  myMethod(\n    @log("Parameter Z") paramZ: string,\n    @log("Parameter Y") paramY: number\n  ) {\n    console.log("Metoden myMethod blev udført.");\n  }\n\n  @log("Getter/Setter F")\n  get myAccessor() {\n    return "";\n  }\n\n  set myAccessor(value: string) {\n    //...\n  }\n\n  constructor() {\n    console.log("Constructor blev udført.");\n  }\n}\n\nnew MyDecoratedClass();\n// Kald metode for at udløse metode-decorator\nnew MyDecoratedClass().myMethod("hello", 123);\n\n/* Forudsagt Output-rækkefølge (omtrentlig, afhængig af specifik TypeScript-version og kompilering):\nParam Decorator: Parameter Y på parameter #1 af myMethod\nParam Decorator: Parameter Z på parameter #0 af myMethod\nProperty Decorator: Statisk Property A på staticProp\nProperty Decorator: Instans Property B på instanceProp\nMetode/Accessor Decorator: Getter/Setter F på myAccessor\nMetode/Accessor Decorator: Metode C på myMethod\nMetode/Accessor Decorator: Metode D på myMethod\nKlasse Decorator: Klasse Niveau C på MyDecoratedClass\nKlasse Decorator: Klasse Niveau D på MyDecoratedClass\nConstructor blev udført.\nMetoden myMethod blev udført.\n*/
            

              
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            import "reflect-metadata"; // Essentiel for emitDecoratorMetadata\n\nconst INJECTABLE_METADATA_KEY = Symbol("injectable");\nconst INJECT_METADATA_KEY = Symbol("inject");\n\nfunction Injectable() {\n  return function (target: Function) {\n    Reflect.defineMetadata(INJECTABLE_METADATA_KEY, true, target);\n  };\n}\n\nfunction Inject(token: any) {\n  return function (target: Object, propertyKey: string | symbol, parameterIndex: number) {\n    const existingInjections: any[] = Reflect.getOwnMetadata(INJECT_METADATA_KEY, target, propertyKey) || [];\n    existingInjections[parameterIndex] = token;\n    Reflect.defineMetadata(INJECT_METADATA_KEY, existingInjections, target, propertyKey);\n  };\n}\n\nclass Container {\n  private static instances = new Map<any, any>();\n\n  static resolve<T>(target: { new (...args: any[]): T }): T {\n    if (Container.instances.has(target)) {\n      return Container.instances.get(target);\n    }\n\n    const isInjectable = Reflect.getMetadata(INJECTABLE_METADATA_KEY, target);\n    if (!isInjectable) {\n      throw new Error(`Klassen ${target.name} er ikke markeret som @Injectable.`);\n    }\n\n    // Hent constructor-parametrers typer (kræver emitDecoratorMetadata)\n    const paramTypes: any[] = Reflect.getMetadata("design:paramtypes", target) || [];\n    const explicitInjections: any[] = Reflect.getMetadata(INJECT_METADATA_KEY, target) || [];\n\n    const dependencies = paramTypes.map((paramType, index) => {\n      // Brug eksplicit @Inject-token hvis angivet, ellers udled typen\n      const token = explicitInjections[index] || paramType;\n      if (token === undefined) {\n        throw new Error(`Kan ikke resolvere parameter ved indeks ${index} for ${target.name}. Det kan være en cirkulær afhængighed eller primitiv type uden eksplicit @Inject.`);\n      }\n      return Container.resolve(token);\n    });\n\n    const instance = new target(...dependencies);\n    Container.instances.set(target, instance);\n    return instance;\n  }\n}\n\n// Definer services\n@Injectable()\nclass DatabaseService {\n  connect() {\n    console.log("Forbinder til database...");\n    return "DB Forbindelse";\n  }\n}\n\n@Injectable()\nclass AuthService {\n  private db: DatabaseService;\n\n  constructor(db: DatabaseService) {\n    this.db = db;\n  }\n\n  login() {\n    console.log(`AuthService: Godkender ved hjælp af ${this.db.connect()}`);\n    return "Bruger logget ind";\n  }\n}\n\n@Injectable()\nclass UserService {\n  private authService: AuthService;\n  private dbService: DatabaseService; // Eksempel på injektion via property ved hjælp af en custom decorator eller framework-funktion\n\n  constructor(@Inject(AuthService) authService: AuthService,\n              @Inject(DatabaseService) dbService: DatabaseService) {\n    this.authService = authService;\n    this.dbService = dbService;\n  }\n\n  getUserProfile() {\n    this.authService.login();\n    this.dbService.connect();\n    console.log("UserService: Henter brugerprofil...");\n    return { id: 1, name: "Global Bruger" };\n  }\n}\n\n// Resolv hoved-servicen\nconsole.log("--- Resolver UserService ---");\nconst userService = Container.resolve(UserService);\nconsole.log(userService.getUserProfile());\n\nconsole.log("\n--- Resolver AuthService (skal være cachet) ---");\nconst authService = Container.resolve(AuthService);\nauthService.login();
            

              
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            function LogMethod(target: any, propertyKey: string, descriptor: PropertyDescriptor) {\n  const originalMethod = descriptor.value;\n  descriptor.value = function (...args: any[]) {\n    console.log(`[LOG AOP] Går ind i metode: ${String(propertyKey)} med args:`, args);\n    try {\n      const result = originalMethod.apply(this, args);\n      console.log(`[LOG AOP] Forlader metode: ${String(propertyKey)} med resultat:`, result);\n      return result;\n    } catch (error: any) {\n      console.error(`[LOG AOP] Fejl i metode ${String(propertyKey)}:`, error.message);\n      throw error;\n    }\n  };\n  return descriptor;\n}\n\nclass PaymentProcessor {\n  @LogMethod\n  processPayment(amount: number, currency: string) {\n    if (amount <= 0) {\n      throw new Error("Betalingsbeløb skal være positivt.");\n    }\n    console.log(`Behandler betaling på ${amount} ${currency}...`);\n    return `Betaling på ${amount} ${currency} behandlet succesfuldt.`;\n  }\n\n  @LogMethod\n  refundPayment(transactionId: string) {\n    console.log(`Refunderer betaling for transaktions-ID: ${transactionId}...`);\n    return `Refundering igangsat for ${transactionId}.`;\n  }\n}\n\nconst processor = new PaymentProcessor();\nprocessor.processPayment(100, "USD");\ntry {\n  processor.processPayment(-50, "EUR");\n} catch (error: any) {\n  console.error("Fangede fejl:", error.message);\n}
            

              
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            interface FieldValidationRule {\n  property: string | symbol;\n  validator: (value: any) => boolean;\n  message: string;\n}\n\nconst fieldValidationRules = new Map<Function, FieldValidationRule[]>();\n\nfunction addValidationRule(target: Object, propertyKey: string | symbol, validator: (value: any) => boolean, message: string) {\n  const rules = fieldValidationRules.get(target.constructor) || [];\n  rules.push({ property: propertyKey, validator, message });\n  fieldValidationRules.set(target.constructor, rules);\n}\n\nfunction IsPositive(target: Object, propertyKey: string | symbol) {\n  addValidationRule(target, propertyKey, (value: number) => value > 0, `${String(propertyKey)} skal være et positivt tal.`);\n}\n\nfunction MaxLength(maxLength: number) {\n  return function (target: Object, propertyKey: string | symbol) {\n    addValidationRule(target, propertyKey, (value: string) => value.length <= maxLength, `${String(propertyKey)} må højst være ${maxLength} tegn langt.`);\n  };\n}\n\nclass Product {\n  @MaxLength(50)\n  name: string;\n\n  @IsPositive\n  price: number;\n\n  constructor(name: string, price: number) {\n    this.name = name;\n    this.price = price;\n  }\n\n  static validate(instance: any): string[] {\n    const errors: string[] = [];\n    const rules = fieldValidationRules.get(instance.constructor) || [];\n    for (const rule of rules) {\n      if (!rule.validator(instance[rule.property])) {\n        errors.push(rule.message);\n      }\n    }\n    return errors;\n  }\n}\n\nconst product1 = new Product("Laptop", 1200);\nconsole.log("Produkt 1 fejl:", Product.validate(product1)); // []\n\nconst product2 = new Product("Meget langt produktnavn der overskrider halvtreds tegns grænsen for testformål", 50);\nconsole.log("Produkt 2 fejl:", Product.validate(product2)); // [\"name må højst være 50 tegn langt.\"]\n\nconst product3 = new Product("Bog", -10);\nconsole.log("Produkt 3 fejl:", Product.validate(product3)); // [\"price skal være et positivt tal.\"]
            

              
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            // En decorator, der sikrer, at en metode logges og også kræver admin-roller\nfunction AdminAndLoggedMethod() {\n  return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {\n    // Anvend Authorization først (indre)\n    Authorization(["admin"])(target, propertyKey, descriptor);\n    // Anvend derefter LogCall (ydre)\n    LogCall(target, propertyKey, descriptor);\n\n    return descriptor; // Returner den modificerede descriptor\n  };\n}\n\nclass AdminPanel {\n  @AdminAndLoggedMethod()\n  deleteUserAccount(userId: string) {\n    console.log(`Sletter brugerkonto: ${userId}`);\n    return `Bruger ${userId} slettet.`;\n  }\n}\n\nconst adminPanel = new AdminPanel();\nadminPanel.deleteUserAccount("user007");\n/* Forventet Output (antaget admin-rolle):\n[AUTH] Adgang givet for deleteUserAccount\n[LOG] Kalder deleteUserAccount med args: [ 'user007' ]\nSletter brugerkonto: user007\n[LOG] Metode deleteUserAccount returnerede: Bruger user007 slettet.\n*/
            

              
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            function ApplyMixins(constructors: Function[]) {\n  return function (derivedConstructor: Function) {\n    constructors.forEach(baseConstructor => {\n      Object.getOwnPropertyNames(baseConstructor.prototype).forEach(name => {\n        Object.defineProperty(\n          derivedConstructor.prototype,\n          name,\n          Object.getOwnPropertyDescriptor(baseConstructor.prototype, name) || Object.create(null)\n        );\n      });\n    });\n  };\n}\n\nclass Disposable {\n  isDisposed: boolean = false;\n  dispose() {\n    this.isDisposed = true;\n    console.log("Objekt kasseret.");\n  }\n}\n\nclass Loggable {\n  log(message: string) {\n    console.log(`[Loggable] ${message}`);\n  }\n}\n\n@ApplyMixins([Disposable, Loggable])\nclass MyResource implements Disposable, Loggable {\n  // Disse properties/metoder injiceres af decoratoren\n  isDisposed!: boolean;\n  dispose!: () => void;\n  log!: (message: string) => void;\n\n  constructor(public name: string) {\n    this.log(`Ressource ${this.name} oprettet.`);\n  }\n\n  cleanUp() {\n    this.dispose();\n    this.log(`Ressource ${this.name} ryddet op.`);\n  }\n}\n\nconst resource = new MyResource("NetworkConnection");\nconsole.log(`Er kasseret: ${resource.isDisposed}`);\nresource.cleanUp();\nconsole.log(`Er kasseret: ${resource.isDisposed}`);
            

              
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