!! Work in progress

Repository pattern & Dependency injection using TypeScript

This starter kit tries to implement a NodeJS, ExpressJS and MongoDB powered web application using repository pattern and dependency injection. The main idea is independent of any framework or database. TypeScript is used instead of JavaScript for various reasons. Especially the support for interface, generic type support, and better IntelliSense.

Usage

• Install required modules (pnpm install)
• Run (pnpm start)
• Go to http://localhost:3000. You should see a static html page.

Note: Run pnpm run start:dev for hot-reload.

Core Features

• Dependency injection
• Repository pattern
• CI (with code coverage) using Azure DevOps

Dependency injection using InversifyJS

InversifyJS is a very useful library for dependency injection in JavaScript. It has first class support for TypeScript. It is not necessary to use interface to use dependency injection because Inversify can work with class. But, we should "depend upon Abstractions and do not depend upon concretions". So we will use interfaces (abstractions). Everywhere in our application, we will only use (import) interfaces. In the src/core/inversify.ts file we will create a container, import necessary classes and do dependency bindings. InversifyJS requires a library named reflect-metadata.

Repository pattern

Main purpose is to decoupte database from business logic. If you ever decide to change the databse then you only need to update repositories. The base repository is src/core/repository.ts. All other repositores should be derived from it (Ex: user.repository.ts).

Continious integration

The Azure Pipeline uses azure-pipelines.yml configuration file. The value of $(DB_PASSWORD), $(DB_USERNAME) etc placeholders should be replaced by pipeline variables. It published both test and coverage result.

This might not be the best implementation you have seen or might not follow all the principals.