[Refactor]: Centralize hardcoded data-type name strings into a package-level object

[Eshaan-byte]

Problem

Data-type name strings ("landings", "index", "age_comp", "length_comp") are hardcoded inline in multiple places, e.g., distribution_formulas.R:33 has a FIXME asking for this exact change. #1247 standardised the naming but the centralisation was never done.

If a new data type is added or a name changes, every call site has to be found and updated manually.

Proposal

Define a single authoritative vector (e.g., fims_data_types) as internal package data or a package-level constant, and replace all inline occurrences with references to it.

Related issues

• Follow-up to [Developer Issue]: inconsistent formatting of data-type names #1247 (naming was standardized, but not centralized)
• [Feature]: Design names for output labels #556 (output label naming conventions)

[Eshaan-byte]

Hi @kellijohnson-NOAA, I'm happy to take this on if you'd like. My plan would be to:

1. Define an internal constant (e.g., fims_data_types) in a dedicated file
2. Replace all inline occurrences across distribution_formulas.R, fimsframe.R, etc.
3. Add tests to verify the constant is used consistently

Let me know if this approach works or if you'd prefer a different direction.

[kellijohnson-NOAA]

@Eshaan-byte I am so sorry that this notification slipped through my inbox. We are happy to have you work on this and your proposal sounds good to me. Let me know if you still have time/desire to work on this.
Regarding (1) maybe we should name it FIMSFrame_types

[Bai-Li-NOAA]

@kellijohnson-NOAA If I understand correctly, fims_input_types has already been merged into main through PR #1293, and fims_distributions will be added to FIMS through PR #1678.

Are there any additional tasks that need to be completed for this issue? I’m just checking in because this issue is tied to the parent issue #1602, which is assigned to me.

[kellijohnson-NOAA]

You are right, somehow closing this issue was missed.