naporin0624 CQRS Pattern
Core Principle
| Aspect | Query (Read) | Command (Write) |
|---|---|---|
| Return Type | Observable<T> |
ResultAsync<void, Error> |
| Side Effects | None | Database writes, notifications |
Resources
| Topic | File |
|---|---|
| Service interface design | SERVICE-INTERFACE.md |
| Observable patterns | OBSERVABLE-PATTERN.md |
| Result types | RESULT-TYPES.md |
| Main process subscription | MAIN-PROCESS-SUBSCRIPTION.md |
Quick Reference
interface UserService {
// Queries → Observable
list(): Observable<User[]>;
get(id: string): Observable<User | undefined>;
// Commands → ResultAsync
create(data: CreateUserData): ResultAsync<void, ApplicationError>;
}
Use BehaviorSubject to bridge: commands trigger #notify.next(), queries subscribe to it.