57 lines
1.2 KiB
TypeScript
57 lines
1.2 KiB
TypeScript
import { Arr } from "../types.ts";
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import { pushIter, addIterUtils } from "./util/mod.ts";
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type Listener<T> = { push: (arg: T) => void; done: () => void };
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export type IterSource<T extends Arr> = ReturnType<typeof fromCallback<T>>;
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export function fromCallback<T extends Arr>(
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source: (listener: (...values: T) => void) => void,
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disconnect?: () => void
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) {
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let isDone = false;
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let listeners: Listener<T>[] = [];
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function trigger(...values: T) {
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if (isDone) {
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return;
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}
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for (const listener of listeners) {
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listener.push(values);
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}
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}
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source(trigger);
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function done() {
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disconnect?.();
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if (isDone) {
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return;
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}
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for (const listener of listeners) {
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listener.done();
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}
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listeners = [];
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isDone = true;
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}
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function addListener(listener: Listener<T>) {
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listeners.push(listener);
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return () => {
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removeListener(listener);
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};
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}
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function removeListener(listener: Listener<T>) {
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const index = listeners.indexOf(listener);
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listeners.splice(index, 1);
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}
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return {
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iterator: () => {
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const { push, done, getIterator } = pushIter<T>();
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addListener({ push, done });
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return addIterUtils<T>(getIterator());
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},
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disconnect: done,
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};
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}
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