/designPatternsTalk

Primary LanguageJavaScript

DESIGN PATTERNS

Codebase that accompanied talk @iCappsBarcamp Feb 2017 on design patterns in Node.js in the light of code quality and automated testing.

The goal is to create code

- with high cohesion (SRP)

- loose coupling (DInj & DInv)

This way it is easily testable in isolation (London style vs Chicago style).

INSTALLATION

  • npm install -g yarn

  • yarn install

  • Install mongodb. You can use the docker-compose.yml for convenience. Just run docker-compose up

  • yarn start to start the server

TESTING

  • yarn test

Browse design patterns implementations

You can browse this repo by its branches.

master

Contains the starter code, loosely based on Marco Casciaro's example in his excellent book on Design Patterns in Node. Here you may find a tight coupling between the domain layer and the data layer. The only way to test the services in isolation from the database, would be to use something like proxyquire, which hacks directly into the node require module. Not a pretty sight :-/

schema 1

dependencyInjection

This branch implements basic DI and wires up the modules at the highest level. Clean testing assured, but database specific syntax is still present in domain layer.

schema 2

dependencyInversion

Implementation of Repository and Factory pattern. Database specific syntax is now abstracted behind a repository and the structure of the domain object is decoupled from the data structure.

schema 3

what else?

A last step would be the introduction of a DI container in order to simplify the module wiring.