Scheduling tests

gistfile1.js

/**
 * Queue of functions to invoke
 * @type {Array<(time: number) => void>}
 */
let callbacks = [];

let channel = new MessageChannel();

let postMessage = (function() {
  this.postMessage(undefined);
}).bind(channel.port2);

// Flush the callback queue when a message is posted to the message channel
channel.port1.onmessage = () => {
  // Reset the callback queue to an empty list in case callbacks call
  // afterFrame. These nested calls to afterFrame should queue up a new
  // callback to be flushed in the following frame and should not impact the
  // current queue being flushed
  let toFlush = callbacks;
  callbacks = [];
  let time = performance.now();
  for (let i = 0; i < toFlush.length; i++) {
    // Call all callbacks with the time the flush began, similar to requestAnimationFrame
    // TODO: Error handling?
    toFlush[i](time);
  }
};

// If the onmessage handler closes over the MessageChannel, the MessageChannel never gets GC'd:
channel = null;

$0.onclick = () => {
  long();

  scheduler.postTask(() => performance.mark("postTask"), {
    priority: "background",
  });

  requestIdleCallback(() => {
    performance.mark("rIC");

    requestIdleCallback(() => {
      performance.mark("rIC2");
      requestIdleCallback(() => performance.mark("rIC3"));
    });

    scheduler.postTask(() => performance.mark("postTask-bg-in-rIC"), {
        priority: "background",
    });
  
    scheduler.postTask(() => performance.mark("postTask-visible-in-rIC"), {
        priority: "user-visible",
    });
  
    scheduler.postTask(() => performance.mark("postTask-blocking-in-rIC"), {
        priority: "user-blocking",
    });
  
    scheduler.yield().then(() => performance.mark("yield-in-rIC"));

    long();
  });

  requestAnimationFrame(() => {
    performance.mark("rAF");
    
    callbacks.push(() => performance.mark("afterFrame-first"))
    postMessage()

    setTimeout(() => {
      performance.mark("setTimeout0");
      long();
    });

    setTimeout(() => performance.mark("setTimeout1"), 1);

    requestIdleCallback(() => performance.mark("rIC-in-rAF"));

    scheduler.postTask(() => performance.mark("postTask-bg-in-rAF"), {
      priority: "background",
    });

    scheduler.postTask(() => performance.mark("postTask-visible-in-rAF"), {
        priority: "user-visible",
    });
    
    scheduler.yield().then(() => performance.mark("yield-in-rAF-before-blocking"));

    scheduler.postTask(() => performance.mark("postTask-blocking-in-rAF"), {
        priority: "user-blocking",
    });

    scheduler.yield().then(() => performance.mark("yield-in-rAF-after-blocking"));
    
    callbacks.push(() => performance.mark("afterFrame-last"))
    postMessage()
  });
};

function long() {
  const perf = performance.now();
  while (true) {
    if (performance.now() - perf > 100) break;
  }
}