Separate application code from configuration
Keep source code, tests, build configuration and generated output distinct. Generated folders should not become the place where developers manually edit files.
Organize by responsibility
For a small application, folders such as components, lib, services and types can be enough. As the project grows, grouping related files by feature can reduce cross-project searching.
Keep boundaries explicit
If a function talks to an API, keep that responsibility close to the API layer. If a component only renders data, avoid hiding network requests inside it unless there is a strong reason.
Use types to explain intent
TypeScript is most useful when types express real domain rules rather than simply converting every JavaScript value to any. Good names and narrow types reduce ambiguity and make refactoring safer.
Prefer simple conventions
A structure should help the team work. If a folder convention requires a long document to explain it, it may be too complicated for the project.