Arnauld

There are certain files created by particular editors, IDEs, operating systems, etc., that do not belong in a repository. But adding system-specific files to the repo's .gitignore is considered a poor practice. This file should only exclude files and directories that are a part of the package that should not be versioned (such as the node_modules directory) as well as files that are generated (and regenerated) as artifacts of a build process.

All other files should be in your own global gitignore file. Create a file called .gitignore in your home directory and add anything you want to ignore. You then need to tell git where your global gitignore file is.

Mac

git config --global core.excludesfile ~/.gitignore

Windows

git config --global core.excludesfile %USERPROFILE%\.gitignore

Arnauld

Handlers

In Domain Driven Design, there are a series of small services that sit over the top of the domain. These services known as Application Services act as a facade over the the domain model. In CQRS based systems a similar pattern is used but it has been slightly refined. The refining of this pattern can be employed successfully in both systems that use CQRS and systems that stay using a single model for supporting reads and writes as many of the advantages come from simplicity of composition. To show Command Handlers, it is best to start with a typical Application Service and refactor our way to a Command Handler.

The Application Service

A stereotypical Application Service represents a given use case of the model. The Application Service itself generally does not directly implement the use case but instead coordinates objects from the domain to meet the requirements of the use case. This sounds like a small distinction but it is  a very important one, Application Services generally should not have "l