import { AsyncAction } from './AsyncAction';
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import { AsapScheduler } from './AsapScheduler';
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import { SchedulerAction } from '../types';
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import { immediateProvider } from './immediateProvider';
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import { TimerHandle } from './timerHandle';
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export class AsapAction<T> extends AsyncAction<T> {
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constructor(protected scheduler: AsapScheduler, protected work: (this: SchedulerAction<T>, state?: T) => void) {
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super(scheduler, work);
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}
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protected requestAsyncId(scheduler: AsapScheduler, id?: TimerHandle, delay: number = 0): TimerHandle {
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// If delay is greater than 0, request as an async action.
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if (delay !== null && delay > 0) {
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return super.requestAsyncId(scheduler, id, delay);
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}
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// Push the action to the end of the scheduler queue.
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scheduler.actions.push(this);
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// If a microtask has already been scheduled, don't schedule another
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// one. If a microtask hasn't been scheduled yet, schedule one now. Return
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// the current scheduled microtask id.
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return scheduler._scheduled || (scheduler._scheduled = immediateProvider.setImmediate(scheduler.flush.bind(scheduler, undefined)));
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}
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protected recycleAsyncId(scheduler: AsapScheduler, id?: TimerHandle, delay: number = 0): TimerHandle | undefined {
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// If delay exists and is greater than 0, or if the delay is null (the
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// action wasn't rescheduled) but was originally scheduled as an async
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// action, then recycle as an async action.
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if (delay != null ? delay > 0 : this.delay > 0) {
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return super.recycleAsyncId(scheduler, id, delay);
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}
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// If the scheduler queue has no remaining actions with the same async id,
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// cancel the requested microtask and set the scheduled flag to undefined
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// so the next AsapAction will request its own.
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const { actions } = scheduler;
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if (id != null && actions[actions.length - 1]?.id !== id) {
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immediateProvider.clearImmediate(id);
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scheduler._scheduled = undefined;
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}
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// Return undefined so the action knows to request a new async id if it's rescheduled.
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return undefined;
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}
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}
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