Angular API Reference

Hand-written reference for everything @useoptimus/angular exports today (packages/angular/src/index.ts). See the Angular adapter guide for usage.

provideFeatureFlags(client, snapshot?)

function provideFeatureFlags(client: FlagsClient, snapshot?: SerializedSnapshot): EnvironmentProviders;

Registers FLAGS_CLIENT/FLAGS_SNAPSHOT and FeatureFlagService. Call only from root bootstrapApplication() providers unless a route-scoped client is deliberately wanted — never calls client.init()/client.dispose() itself, and a lazy route’s EnvironmentInjector teardown is a real (not dev-only) event.

FeatureFlagService

@Injectable()
class FeatureFlagService {
  flag$<T = boolean>(key: string): Observable<EvaluatedFlag<T>>;
  setContext(context: EvaluationContext): void;
}

flag$(key) has no per-call context parameter — deliberately narrower than the React adapter’s useFlag(key, context), since FlagsClient only exposes one ambient, mutable context field and Angular has no per-render-scoped unit to hang a stateless override off of. Every caller shares the one ambient context; setContext() is the only way to change it, and flips the service from snapshot mode to live mode.

In snapshot mode, flag$(key) returns an Observable that emits the hydrated snapshot’s value for key once, synchronously — no client calls. In live mode it’s shareReplay({ bufferSize: 1, refCount: true })-cached per key, re-emitting on client.subscribe() updates for that key and on setContext() calls.

IfFeatureDirective

@Directive({ selector: "[ifFeature]", standalone: true })
class IfFeatureDirective implements OnInit {
  ifFeature: string; // required input
}

Structural directive (*ifFeature="'key'"). Shows/hides its template based on plain Boolean(flag.value) truthiness for any flag shape (boolean, variant, or value alike) — no valueType-specific branching. For variant-specific rendering, use flag$(key) | async with *ngSwitch directly instead.

Tokens

const FLAGS_CLIENT: InjectionToken<FlagsClient>;
const FLAGS_SNAPSHOT: InjectionToken<SerializedSnapshot | undefined>;

Injection tokens provideFeatureFlags registers FeatureFlagService against. Only needed directly if you’re constructing the provider set by hand instead of via provideFeatureFlags.

FlagsClient, EvaluationContext, and EvaluatedFlag<T> come from @useoptimus/core; SerializedSnapshot comes from @useoptimus/node.