DomEventLoop Class

Gets or sets whether queued microtasks run synchronously at the end of each DOM operation that queued them.

Gets whether asynchronous operations are in progress (e.g. documents loaded by BrowsingContextOptions.DocumentLoader). They queue a task when they complete.

Gets whether there are pending tasks or microtasks.

Gets whether a worker created by the documents of the event loop (or by its workers) has a task to run, or runs a task that is not waiting for a synchronous operation: a host that advances a fake clock waits for the workers before advancing it.

Gets whether the event loop was disposed with its browsing context (BrowsingContext.Dispose): the tasks, the microtasks and the timers queued afterwards are ignored.

Gets or sets a function that queues microtasks in another queue (for instance the job queue of a JavaScript engine), so that microtasks queued by the DOM and by scripts are interleaved in order.

Gets or sets the clock of the timers (setTimeout(), requestAnimationFrame(), AbortSignal.timeout()...) and of performance.now(). The default is TimeProvider.System. A browsing context created with BrowsingContextOptions.TimeProvider sets it. Use a fake clock (e.g. FakeTimeProvider) to run the timers without waiting.

Gets or sets a function that schedules the timers of the DOM (e.g. AbortSignal.timeout()) in the host's own timer queue, so they are ordered with the other timers of the host.

Gets or sets the callback invoked when work arrives, from any thread: a task is queued (e.g. by an asynchronous operation that completes on another thread, such as a document loaded by BrowsingContextOptions.DocumentLoader), a timer is queued, or an asynchronous operation ends. A host that runs the event loop on its own thread uses it to wake up and call DomEventLoop.RunTask and DomEventLoop.PromoteDueTimers. The callback must not run the event loop itself.

Gets a value that changes each time a worker created by the documents of the event loop (or by its workers) stops running (see DomEventLoop.HasRunningWorkers): it ran a task, or its task waits for a synchronous operation. A worker may run between two reads of DomEventLoop.HasRunningWorkers (e.g. its timer becomes due when another thread reads the clock) and add a timer or queue a task meanwhile: a host that advances a fake clock reads this value before computing the next timer, and does not advance the clock if it changed.

https://html.spec.whatwg.org/multipage/webappapis.html#perform-a-microtask-checkpoint

Moves the due timers to the task queue. Returns the time until the next timer, or null when there is none. The timers of the workers created by the documents of the event loop are included in the result (they run on the threads of the workers), so that a host that advances a fake clock to the next timer also runs the timers of the workers.

https://html.spec.whatwg.org/multipage/webappapis.html#queue-a-microtask

Queues a task (https://html.spec.whatwg.org/multipage/webappapis.html#queue-a-task).

Queues a task after a delay (e.g. setTimeout() or AbortSignal.timeout()), measured with DomEventLoop.TimeProvider. The timers are moved to the task queue once they are due (DomEventLoop.PromoteDueTimers, DomEventLoop.RunUntilIdle). The timers that are due at the same time run in the order they were queued.

Runs one task, followed by a microtask checkpoint. Returns false when there is no task. The tasks run in the order they were queued, except the tasks of the schedulers (Scheduler.PostTask, Scheduler.Yield), which run in the order of their priorities: see DomEventLoop.SelectNextSchedulerTaskQueue. When no task is queued, an idle period runs the idle callbacks of the windows (Window.RequestIdleCallback).

Runs the microtasks and the tasks until both queues are empty.

Runs the microtasks and the tasks until both queues are empty and no asynchronous operation is in progress (e.g. the documents loaded by BrowsingContextOptions.DocumentLoader).

Waits until the next timer is due, using DomEventLoop.TimeProvider (e.g. until a fake clock is advanced), and moves it to the task queue. Returns false when there is no timer and no task. For instance, to run the tasks and the timers until there is nothing left: do { await eventLoop.RunUntilIdleAsync(); } while (await eventLoop.WaitForNextTimerAsync());