dic tool 🧰

dic tool y part of the NodeTskeleton template project.

NodeTskeleton is a Clean Architecture based template project for NodeJs using TypeScript to implement with any web server framework or even any user interface.

Go to NodeTskeleton

What is dic-tsk?

The dependency injection container dic is a tool that will allow us to manage the class instances for your software solution in scoped or singleton way.

Using dic

If you are using Clean Architecture you should create a directory in adapter layer path like adapters/shared/kernel and inside this directory we need to create a index file with the next content:

import applicationStatus from "../../../application/shared/status/applicationStatus";
import appMessages, { localKeys } from "../../../application/shared/locals/messages";
import tsKernel, { IServiceContainer } from "dic-tsk";

// This method is for customization but is optional
tsKernel.init({
  internalErrorCode: applicationStatus.INTERNAL_ERROR,
  classNameBase: "",
  interfaceBaseName: "",
  appMessages,
  appErrorMessageKey: localKeys.DEPENDENCY_NOT_FOUNT,
  applicationStatus,
  applicationStatusCodeKey: "INTERNAL_ERROR",
});

export { IServiceContainer };
export default tsKernel;

Important note

init method is optional, you don't need use it but is better for your customization because the kernel has the minimum resources to works, so the internal default values that it use are:

internalErrorCode = "FF";
classNameBase = "KeyClassName";
interfaceBaseName = "IKeyClassName";
appErrorMessageKey = "DEPENDENCY_NOT_FOUNT";
applicationStatusCodeKey = "INTERNAL_ERROR";

Probably the only configuration you need to do in your software solution is to map the internal value of the internalErrorCode = "FF" into your application code dictionary.

In action

dic kernel has two ways to manage our class instances, scoped and singleton

Scoped way

Scoped way return a new instance for each call to get method like following:

import { LoginUseCase } from "../../../../application/modules/auth/useCases/login";
import { AuthProvider, LogProvider } from "../../../providers/container";
import kernel from "../../../shared/kernel";

const CONTEXT = `AuthControllerContainer`;

kernel.addScoped(
  LoginUseCase.name,
  () =>
    new LoginUseCase(
      kernel.get<LogProvider>(CONTEXT, LogProvider.name),
      kernel.get<AuthProvider>(CONTEXT, AuthProvider.name),
    ),
);

export { LoginUseCase };
export default kernel;

// In another module
import container, { LoginUseCase } from "./container";

const useCase = this.servicesContainer.get<LoginUseCase>(this.CONTEXT, LoginUseCase.name);
useCase.execute(params);

Singleton way

Singleton way return the same instance always for each call to get method like following:

import { AuthProvider } from "../../../providers/container";
import kernel from "../../../shared/kernel";

const CONTEXT = `ProviderContainer`;

kernel.addSingleton(
  AuthProvider.name,
  new AuthProvider(
    kernel.get<LogProvider>(CONTEXT, LogProvider.name),
  ),
);

export { AuthProvider };
export default kernel;

// In another module
import container, { LogProvider } from "./container";

const logProvider = this.servicesContainer.get<LogProvider>(this.CONTEXT, LogProvider.name);

Important note

Note that the singleton pattern can become very useful, but mishandling this pattern can end up in mutation problems, a very common mistake in JavaScript that can cause you a lot of headaches.

Errors

When you try to get a not existing class so, the dic kernel throw an error as following:

const auditProvider = this.servicesContainer.get<AuditProvider>(this.CONTEXT, AuditProvider.name);
/* 
The artifact will throw an error like the following:
- Without init method: ApplicationError: 'NotExistsClass' not found in dependencies container.
- With previous call of init method: ApplicationError: WITH YOUR CUSTOM MESSAGE if it was customized.
*/

RunKit demo

Go to this Link or click in Try on RunKit button on the right side of the page.

Warning 💀

Use this resource at your own risk.