Validation And Behavior

Core queries validate input and provide predictable execution behavior.

Client-Side Validation

Validation metadata is generated from backend FluentValidation rules through the proxy generator.

const query = new SearchUsersQuery();
query.parameters = { searchTerm: 'ab', minAge: -5 };

const result = await query.perform();
// result.isValid === false
// result.validationResults contains validation errors

Observable queries validate the same way. perform() returns an invalid result, and subscribe() delivers one to your callback instead of opening a connection:

const query = new ObserveUsers();

query.subscribe(result => {
    // result.isValid === false when the arguments were rejected,
    // which is distinct from a valid result that simply has no data yet
}, { minAge: -5 });

Because subscribe() validates the arguments it is given, a subscription started before its arguments are available is rejected rather than left open. Gate it with ObservableQueryWhen so the subscription only starts once the arguments exist:

<ObservableQueryWhen condition={!!authorId}>
    {/* subscribes only once authorId has a value */}
</ObservableQueryWhen>

Client-side validation is a convenience, not a gate — every rule it applies is also enforced by the server, so calling an endpoint directly gains nothing. Server rejections report member names the same way the client does: camelCased, and attributed to the field rather than to a concept’s inner value.

For general validation docs, see Validation.

Sorting And Paging

Queries include native sorting and paging primitives via Sorting and Paging.

For React usage patterns and generated hooks, see Paging.

Request Cancellation

When a newer request supersedes an active one, Arc cancels stale work to reduce race conditions and unnecessary processing.

Error Categories

Typical query failure categories include:

• Parameter validation errors
• Network failures
• Timeouts and cancellations
• Server exceptions

See Also

• Query Contracts
• React Queries