Correct Grouping of related Entities

[stsiushkevich]

Hello! I have a typical situation when there are some set of related entities(slices). For example we have Employee entity, and related EmployeeGroup and EmployeeRoleGroup entities and appropriate TS Types. For all of them there are according data lists, that displayed on the page and fetching data from the server. Should I leave these slices like separated at the same @entities layer, or unite them to a single slice Employee?

[illright]

I would recommend keeping the slices flat as long as possible, and only when it starts to overflow with slices, you can start grouping them. Note that when you group slices into a folder, they don't become one slice. In the case below:

• entities/
  • Employee/
    • Person/
    • Group/
    • RoleGroup/
  • Identification/

The slices are Employee/Person, Employee/Group, and Employee/RoleGroup, and these slices are bound by the same rules as Identification, no code sharing is permitted between Employee/* slices.

[stsiushkevich]

Ok, but can the following structure be alternatively approach that you described:
@entities/Employee/api/services/EmployeeService
@entities/Employee/api/services/EmployeeGroupService
@entities/Employee/api/services/EmployeeRoleGroupService

@entities/Employee/ui/EmployeeList
@entities/Employee/ui/EmployeeGroupList
@entities/Employee/ui/EmployeeRoleGroupList

...... etc.......

So here we have only one single common/collective slice Employee, but many entities in it. Or maybe it is bad approach because it can seem that we can use entity EmployeeList from EmployeeGroupList for example?

[illright]

This is a perfectly valid approach too. Usually you should split an entity into several entities (potentially grouped) when the single entity becomes unmaintainable. Most decisions in FSD are ruled by the principle of Pain-Driven Development: do something only when not doing it causes you pain. If keeping it all inside the Employee entity is fine, do that.

it is bad approach because it can seem that we can use entity EmployeeList from EmployeeGroupList for example
For the reasons described above, it's not bad. The rules of slice isolation are meant to provoke thinking, but in some cases no thinking is required. It's not automatically bad when one business entity uses another, but only as long as they are contained within a single slice (so from the perspective of FSD, they are all just one entity). It depends on how deeply you want to decompose.

[stsiushkevich]

Thank you a lot!