scheduleMicrotask function Null safety

void scheduleMicrotask (
  1. void callback(

    Runs a function asynchronously.

    Callbacks registered through this function are always executed in order and are guaranteed to run before other asynchronous events (like Timer events, or DOM events).

    Warning: it is possible to starve the DOM by registering asynchronous callbacks through this method. For example the following program runs the callbacks without ever giving the Timer callback a chance to execute:

    main() { { print("executed"); });  // Will never be executed.
      foo() {
        scheduleMicrotask(foo);  // Schedules [foo] in front of other events.

    Other resources

    • The Event Loop and Dart: Learn how Dart handles the event queue and microtask queue, so you can write better asynchronous code with fewer surprises.


    void scheduleMicrotask(void Function() callback) {
      _Zone currentZone = Zone._current;
      if (identical(_rootZone, currentZone)) {
        // No need to bind the callback. We know that the root's scheduleMicrotask
        // will be invoked in the root zone.
        _rootScheduleMicrotask(null, null, _rootZone, callback);
      _ZoneFunction implementation = currentZone._scheduleMicrotask;
      if (identical(_rootZone, &&
          _rootZone.inSameErrorZone(currentZone)) {
            null, null, currentZone, currentZone.registerCallback(callback));