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import {
createDeferredPromise,
DeferredPromise,
} from '../util/DeferredPromise.js';
import {assert} from '../util/assert.js';
interface Poller<T> {
start(): Promise<T>;
stop(): Promise<void>;
result(): Promise<T>;
}
export class MutationPoller<T> implements Poller<T> {
#fn: () => Promise<T>;
#root: Node;
#observer?: MutationObserver;
#promise?: DeferredPromise<T>;
constructor(fn: () => Promise<T>, root: Node) {
this.#fn = fn;
this.#root = root;
}
async start(): Promise<T> {
const promise = (this.#promise = createDeferredPromise<T>());
const result = await this.#fn();
if (result) {
promise.resolve(result);
return result;
}
this.#observer = new MutationObserver(async () => {
const result = await this.#fn();
if (!result) {
return;
}
promise.resolve(result);
await this.stop();
});
this.#observer.observe(this.#root, {
childList: true,
subtree: true,
attributes: true,
});
return this.#promise;
}
async stop(): Promise<void> {
assert(this.#promise, 'Polling never started.');
if (!this.#promise.finished()) {
this.#promise.reject(new Error('Polling stopped'));
}
if (this.#observer) {
this.#observer.disconnect();
}
}
result(): Promise<T> {
assert(this.#promise, 'Polling never started.');
return this.#promise;
}
}
export class RAFPoller<T> implements Poller<T> {
#fn: () => Promise<T>;
#promise?: DeferredPromise<T>;
constructor(fn: () => Promise<T>) {
this.#fn = fn;
}
async start(): Promise<T> {
const promise = (this.#promise = createDeferredPromise<T>());
const result = await this.#fn();
if (result) {
promise.resolve(result);
return result;
}
const poll = async () => {
if (promise.finished()) {
return;
}
const result = await this.#fn();
if (!result) {
window.requestAnimationFrame(poll);
return;
}
promise.resolve(result);
await this.stop();
};
window.requestAnimationFrame(poll);
return this.#promise;
}
async stop(): Promise<void> {
assert(this.#promise, 'Polling never started.');
if (!this.#promise.finished()) {
this.#promise.reject(new Error('Polling stopped'));
}
}
result(): Promise<T> {
assert(this.#promise, 'Polling never started.');
return this.#promise;
}
}
export class IntervalPoller<T> implements Poller<T> {
#fn: () => Promise<T>;
#ms: number;
#interval?: NodeJS.Timer;
#promise?: DeferredPromise<T>;
constructor(fn: () => Promise<T>, ms: number) {
this.#fn = fn;
this.#ms = ms;
}
async start(): Promise<T> {
const promise = (this.#promise = createDeferredPromise<T>());
const result = await this.#fn();
if (result) {
promise.resolve(result);
return result;
}
this.#interval = setInterval(async () => {
const result = await this.#fn();
if (!result) {
return;
}
promise.resolve(result);
await this.stop();
}, this.#ms);
return this.#promise;
}
async stop(): Promise<void> {
assert(this.#promise, 'Polling never started.');
if (!this.#promise.finished()) {
this.#promise.reject(new Error('Polling stopped'));
}
if (this.#interval) {
clearInterval(this.#interval);
}
}
result(): Promise<T> {
assert(this.#promise, 'Polling never started.');
return this.#promise;
}
}
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