Effection Request Animation Frame Stream

request-animation-frames.ts

import { createSignal, resource, type Stream } from "./mod.ts";

/**
 * Consume RAF's as a Stream.
 *
 * ## Example
 *
 * for (let timestamp of yield* each(requestAnimationFrames)) {
 *  // do work
 *  yield* each.next();
 * }
 */
export const requestAnimationFrames: Stream<number, never> = resource(
  function* (provide) {
    let signal = createSignal<number, never>();
    let id = 0;
    let callback: FrameRequestCallback = (timestamp) => {
      signal.send(timestamp);
      id = requestAnimationFrame(callback);
    };
    id = requestAnimationFrame(callback);
    try {
      yield* provide(yield* signal);
    } finally {
      cancelAnimationFrame(id);
    }
  },
);