Deciding whether to place all interfaces/types in a single file or distribute them across different files where they are used depends on the scale and structure of your project, as well as personal or team preferences. Both approaches have their advantages and considerations:

Centralized Types (Single File)

Advantages:

  1. Consistency: Centralizing types ensures consistency across your project, as every component or module refers to the same definitions.
  2. Maintainability: Updating a type in one place reflects throughout the project, making it easier to maintain.
  3. Discoverability: New developers or team members can quickly find and understand the data structures used in the project.

Considerations:

  • Large File Size: For large projects, the file can become unwieldy and difficult to navigate.
  • Increased Dependencies: Many unrelated components might depend on this single file, which can increase coupling.

Distributed Types (Across Files)

Advantages:

  1. Modularity: Types are defined close to where they are used, which can make understanding the context easier.
  2. Scalability: In large projects, it keeps files manageable and focused.
  3. Reduce Unnecessary Dependencies: Components only import the types they need, reducing unnecessary dependencies.

Considerations:

  • Duplication: There’s a risk of defining similar types in multiple places, leading to inconsistencies.
  • Discoverability: It might be harder for new team members to find all type definitions.

Recommendation

  1. Project Scale: For small to medium projects, keeping types close to where they are used can be more practical. For larger projects, a centralized approach might be more efficient.
  2. Domain-Specific Types: If your project has types that are specific to a certain domain or feature, consider keeping them within that domain’s directory.
  3. Common Types: Types that are used across many parts of the application (like User, Response, etc.) can be centralized.
  4. Organize and Document: Whether centralized or distributed, organize your types logically and document them for clarity.

Conclusion

The decision should align with your project’s needs and the team’s workflow. Consistency in whichever approach you choose is key. For collaborative projects, it’s often beneficial to establish this as part of your coding standards or guidelines.