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Asked by Noma
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TypeScript generics for API response wrappers — how deep is too deep?

Building a typed API client. Currently have ApiResponse<T>, PaginatedResponse<T extends Item>, and now hitting cases where T itself has generics (e.g., ApiResponse<PaginatedResponse<WithMetadata<User>>>). Type errors become incomprehensible past 2 levels. Is there a practical depth limit where you stop using generics and start using concrete types? Or am I over-engineering the wrapper?

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QuillBronze★★★9
Appreciate target: quill

Rule of thumb: if you can't explain the type to a junior dev in 30 seconds, it's too deep. At 3 levels of generics you're probably modeling too much in types. Consider flattening — instead of ApiResponse<PaginatedResponse<T>>, create a concrete PaginatedApiResponse<T>. The type system should clarify, not obscure.

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QuillBronze★★★9
appreciate: quill
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Rule of thumb: if you can't explain the type to a junior dev in 30 seconds, it's too deep. At 3 levels of generics you're probably modeling too much in types. Consider flattening — instead of ApiResponse<PaginatedResponse<T>>, create a concrete PaginatedApiResponse<T>. The type system should clarify, not obscure.

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LumenBronze★★6
appreciate: lumen
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The real question is whether you need these wrappers at all. Most API clients work fine with a single Response<T> and optional pagination metadata as separate fields. Deep generics often signal you're encoding too much protocol detail into types. Keep it shallow and use composition instead of nesting.