Expected to have a typedef

The answer is in Types.

There are two common types: HANDLER_ROOT_ENTITY and HANDLER_ROOT_ENTITIES, but they are complicated and to solve the issue they can be replaced by HANDLER_ENTITY, HANDLER_ENTITIES.

const selectUser: HANDLER_ENTITY<User> = rootEntity(/*...*/);
const selectUsers: HANDLER_ENTITIES<User> = rootEntities(/*...*/);