kitten.sh
1/** A talkback signal is used to tell a [Source] that either the [Sink] is ready for new values or that the stream should be cancelled */
2export const enum TalkbackKind {
3 Pull = 0,
4 Close = 1,
5}
6
7/** A talkback callback is sent to the sink with the [Start] signal to communicate signals back to the source. */
8export type TalkbackFn = (signal: TalkbackKind) => void;
9export type TeardownFn = () => void;
10
11export const enum SignalKind {
12 Start = 0,
13 Push = 1,
14 End = 0,
15}
16
17export interface Tag<T> {
18 tag: T;
19}
20
21/** The start [Signal] is the first signal and carries a callback (talkback) so the sink can send signals to the source */
22export type Start<_T> = Tag<SignalKind.Start> & [TalkbackFn];
23/** The Push [Signal] carries new values to the sink, like in an event emitter */
24export type Push<T> = Tag<SignalKind.Push> & [T];
25
26/** A signal that communicates new events to a sink. */
27export type Signal<T> = Start<T> | Push<T> | SignalKind.End;
28
29/** A sink accepts new values from a [Source], like [Push], [Start], and an end signal. The [Start] is used to receive a callback to send talkback signals back to the source. */
30export type Sink<T> = (signal: Signal<T>) => void;
31/** A source is a function that accepts a [Sink] and then starts sending [Signal]s to it. */
32export type Source<T> = (sink: Sink<T>) => void;
33/** An operator transforms a [Source] and returns a new [Source], potentially with different timings or output types. */
34export type Operator<In, Out> = (a: Source<In>) => Source<Out>;
35
36/** Extracts the type of a given Source */
37export type TypeOfSource<T> = T extends Source<infer U> ? U : never;
38
39export interface Subscription {
40 unsubscribe(): void;
41}
42
43export interface Observer<T> {
44 next(value: T): void;
45 complete(): void;
46}
47
48export interface Subject<T> extends Observer<T> {
49 source: Source<T>;
50}