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