Domains

What Is a Domain?

In Morando, a domain is a folder containing a collection of modules.

Domains are intentionally simpler than modules. Their role is to group related modules under a shared, high-level business area.

Domain Location

Every domain folder must be located at the root of the source code folder. That source code folder is usually called src/, but for simplicity we will be referring to it in the rest of the documentation as @/.

By convention, domain names start with an uppercase letter, just like module names. This makes domains easy to spot and keeps the top-level structure consistent.

Domains Contain Modules

Each module must be placed inside a domain. In other words, modules are never top-level folders on their own. Consequently, domains can contain only modules; files or layer folders cannot be placed directly inside a domain folder. Below is an example structure:

.
├── Checkout/
│   ├── Cart/
│   └── Payment/
├── Catalog/
│   ├── ProductDetails/
│   └── ProductList/
└── DesignSystem/
    ├── Button/
    ├── Dropdown/
    └── Theme/

In this example, Checkout, Catalog, and DesignSystem are domains, and each contains one or more modules.

File path anatomy

Given any path, we can easily identify the domain and module where the file is located. For example, @/Api/Product/useProduct.ts tells us that the useProduct.ts file is part of the Api domain and the Product module.

Domain Dependencies

As with modules, analyzing domain dependencies gives a lot of useful information about the application architecture. Domain A depends on Domain B if any module from Domain A depends on any module from Domain B.

Unlike modules, however, domains can be circularly dependent on each other. If Domain A depends on Domain B, there is nothing preventing Domain B from depending on Domain A.