Clean Code: DataServices

[robertu7]

DataServices such as userService.ts and articleService.ts have a lot of code in a single file, and as our business logic grows, they become difficult to maintain.

[devformatters]

The original design of service is only about data and sql operation. In my view, the business logic should always stay in resolver instead of service.

[guoliu]

The original design of service is only about data and sql operation. In my view, the business logic should always stay in resolver instead of service.

Agreed. Data services are used as data sources of Apollo Server, so we should just expose connections to external services such as database, queue, s3, etc., and leave everything else in resolvers.

[robertu7]

#1628

[devformatters]

Nice PR #2142 💪🏻

[gary02]

the business logic should always stay in resolver instead of service.

But this way makes writing unit tests harder.

Furthermore， sometime, same business logics are needed by multi resolvers. Services are good places to store those business logic for reuse in such case.