Import
import { exists } from "@typed/fx/RefOption";Signatures
export declare const exists: {
<A>(predicate: (a: A) => boolean): <E, R>(ref: RefOption<A, E, R>) => RefSubject.Computed<boolean, E, R>;
<A, E, R>(ref: RefOption<A, E, R>, predicate: (a: A) => boolean): RefSubject.Computed<boolean, E, R>;
};Why
Makes exists a live projection of the option; consumers can sample it now or observe it without copying the source state.
Ownership and lifetime
The exists view retains no independent state. An Effect read samples the source once; Fx observation follows later pushes and its observing Scope owns subscription cleanup.
Other public imports
These import paths expose the same declaration. Each page retains its own public name and signature.