Import
import { countBy } from "@typed/fx/RefIterable";Signatures
export declare const countBy: {
<A>(predicate: (a: A) => boolean): <E, R>(ref: RefIterable<A, E, R>) => RefSubject.Computed<number, E, R>;
<A, E, R>(ref: RefIterable<A, E, R>, predicate: (a: A) => boolean): RefSubject.Computed<number, E, R>;
};Why
Makes count by a live projection of the iterable; consumers can sample it now or observe it without copying the source state.
Ownership and lifetime
The count by 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.